Deliberated system of ternary core–shell polythiophene/ZnO/MWCNTs and polythiophene/ZnO/ox-MWCNTs nanocomposites for brilliant green dye removal from aqueous solutions

Abstract In recent times, great attention has been given to developing extremely competent adsorbents for removing organic dyes from wastewater. Thus, to enhance their adsorption capability, a general strategy based on adsorbent surface modification with polymers has been proposed. This report demonstrates the potential of a ternary mixture of polythiophene/zinc oxide/multiwalled carbon nanotubes (PTh/ZnO/MWCNTs) and tertiary PTh/ZnO/oxidized multiwalled carbon nanotubes (ox-MWCNTs), which have been incorporated via an in-situ method of chemical polymerization through a simplistic two-way method. SEM and EDX outcomes show that ZnO and MWCNTs, or ox-MWCNTs, are well covered with PTh. Raman, FTIR, and XRD demonstrated the effective synthesis of PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs nanocomposites with good interfacial interactions between the components. This report also examined the potential of these nanocomposites to remove brilliant green (B.G.) (a toxic dye) from a water solution. In addition, the influence of adsorption parameters, such as concentration, adsorption temperature, pH, and stirring time, was evaluated. B.G.’s adsorption percentage was affected by concentration, temperature, and time. B.G.’s maximum adsorption potential was 9.1 mg g −1 for PTh/ZnO/ox-MWCNTs and 8.3 mg g −1 for PTh/ZnO/MWCNTs, demonstrating the nanocomposites’ (NCs) potential for effective B.G. adsorption. The outcomes of the dye removal show that the dye removal process was spontaneous and endothermic, as evaluated by thermodynamic and kinetic criteria. Graphical Abstract


Introduction
The pigments used in industry, such as brilliant green (B. G.), Remazol brilliant blue R, crystal violet, methylene blue (M. B.), Congo red, Basic Red 9, amaranth, and indigo carmine, are highly harmful to the environment, as they cause substantial pollution [1]. The key industries that use these pollutant dyes are the leather, printing, rubber, food, cosmetics, and paper industries [2]. When these dyes are discharged into water, they dissolve and pollute the water resources, negatively impacting the food chain and marine life. These dyes are mutagenic and carcinogenic for marine animals and humans, as they cause allergies and susceptible reactions in the body, which leads to skin irritation [3]. One of the dyes, M. B., is very dangerous for animals and humans, as it can cause issues such as bilateral blindness, among others [4]. To examine the dangerous effects of dyes, innovative, and effective methods to treat the dyes have been adopted. Some of these methods include adsorption [5], photocatalytic degeneration [6], chemical oxidation [7], and biodegradation [8]. On examining the efficiency of all the methods, the adsorption method of waste removal is considered the most effective method, as it is a highly simple method that is both easy to operate and costfriendly. This method effectively clears away color, organic, oil, and odor pollutants from the dyes [9]. The development of electronic items, such as displays, batteries, electronic devices, and functional electrodes requires the use of conducting polymers, such as polyaniline, polythiophene, and polypyrrole [7]. Apart from using these conductive polymers in the formation of electric items, technological advancements have made it possible to use them for water purification methods. These polymers target harmful microorganisms [10], pollutants, dyes [11], and bulky metals [12] in the water to purify it. A range of investigations has been performed on conductive polymers to enhance their effectiveness in water purification [7]. Among all conductive polymers, PTh is considered the most efficient polymer, as it can easily be polymerized, is relatively low cost, and has good thermal and environmental stability [13]. Mishra et al., in their study, experimented with forming a transformed conductive PTh polymer. As the modified polymer consisted of amino acids, it displayed high electrostatic appeal between the M.B. dye and positively charged particles. This high electrostatic attraction helped to increase the adsorption power of the polymer [7]. Regardless, PTh has inferior dispersion features and a low surface area resulting from particle agglomerations. Thus, supporting materials are needed to enhance its characteristics. Ansari et al., for the process of basic dye removal, made use of a PTh/sawdust bionanocomposite [4]. Nanoparticles (NPs) have been effective for removing and treating pollutants, and a larger number of studies have confirmed their success [14]. Compared to commercial analogues [15], nanooxides perform more effectively and efficiently as adsorbents. The major reason behind their high effectiveness is that they are easy to synthesize and have greater surface reactivity and adsorption potential [16]. The aqueous adsorption of Janus green B and Fuchsin basic onto NiFe 2 O 4 /PTh nanocomposites (NCs) has recently been reported [17]. For the process of dye removal from waste, another material that can be used and applied in many fields is ZnO NPs, yet only a limited number of reports on ZnO as an adsorbent have been published. Khoshhesab et al. [18] analyzed the adsorption of ZnO NPs with reactive black 8 with a capacity of 27.6 mg/g. Singh et al. [19] carried the research work to another level by oxide-based nanomaterials that aided dye removal. The materials developed were TiO 2, Fe 3 O 4 , and ZnO. A biobased (chitosan/PVA/ZnO) NC film was synthesized for the removal of organic dyes, as reported by Kumar et al. [20]. However, the number of studies on these materials is limited, as their efficiency for dye removal remains limited. The excellent characteristics of carbon nanotubes (CNTs), however, have increased their utilization in advanced applications.
One of the major characteristics of CNTs is that the surfaces of these tubes are insoluble in water [21]. To modify the surface of these tubes, a functionalization method has been developed and adopted. This process is covalent and includes cycloaddition, halogenation, and oxidation methods. In the case of the noncovalent method, modifications, such as the transfer of charge and p-p method are used. Both covalent and noncovalent methods have specific advantages. However, in certain cases, the use of the modified surface method has proven to be ineffective, which has limited the use of this method [22]. The modification of CNTs with the help of transformational strategies has helped to increase their applications in the field of medical, drug delivery, engineering, and electrochemical devices [23]. Mallakpour and Rashidimoghadam prepared starch/MWCNT-vitamin C NCs. They showed that MWCNTs improved dye removal [24]. Other than high surface areas, other qualities of useful modified materials are hallowed/layered structures, surface charge, and high porosity. At the same time, the major role of CNTs was limited to the treatment of wastewater [25]. Additionally, these days, multiwalled carbon nanotubes (MWCNTs), compared with other nanomaterials, have exhibited a comparatively higher efficiency of adsorption for the removal of dyes, heavy metal ions, and volatile organic compounds [26]. A large number of functional groups, such as phenol (-OH), thiol (-SH), amine (-NH 2 ), carboxyl (-COOH), and poly(styrene-co-acrylonitrile), are used to improve the properties of MWCNTs by grafting these functional groups on its surface [22]. Therefore, we proposed combining the properties of ZnO and modified MWCNTs to obtain greater properties and higher adsorption efficiency of dyes. The in situ chemical polymerization process is used in this article to prepare novel polymer NCs based on MWCNTs or ox-MWCNTs, PTh, and ZnO. Carboxylated MWCNT derivatives (ox-MWCNTs) are produced by increasing the number of carboxylic (COOH) groups on the surface of MWCNTs. This derivative has a larger number of adsorption sites and has a negative charge on it. To signify the presence of NCs, different analytical techniques, such as IR, EDX, XRD, Raman spectroscopy, and SEM, were used. The process of removing the B. G. dye with the help of NCs has not been examined in detail. It can be demonstrated that the as-fabricated adsorbent has a higher adsorption capacity than the PTh, which further increases its durability. NCs have emerged as an interesting model material for the removal of B. G. dye. In addition, the various effects of parameters, such as concentration, temperature, and shaking time are also studied in a detailed manner. Furthermore, a detailed study of the kinetics and thermodynamics of the adsorption process was performed, and the reusability of the NCs in other applications was also examined.

Materials and reagents
Fluka (Switzerland) provided ammonium persulfate (APS) and thiophene; Sigma-Aldrich (St. Louis, MO) provided an oil bath, nitric acid (HNO 3 ), sulfuric acid (H 2 SO 4 ), and hydrochloric acid (HCl), and all were utilized directly without any further purification. MWCNTs and ZnO were obtained from Materials Supplier Inc., XFNANOA (Tianjin, China). All chemicals and solvents used in the study were of analytical grade and were employed with no further purification. B.G. dye stock solution obtained from Aldrich Chemical Co Ltd. (Milwaukee), WC, was made for 1000 lg mL À1 . Furthermore, stock solutions (5-50 lg mL À1 ) of the diluted standard were made with deionized water. Several buffers of Bitton-Robinson (B.R.), ranging from 2 pH to 11 pH and 0.1 mol L À1 HCl, were applied as B.G. sorption method's extraction medium by PTh/ZnO/MWCNTs and PTh/ZnO/ ox-MWCNTs (solid phases). The experiment also utilized deionized, distilled, and ultrapure water (DI water). Bottles, other equipment, and glassware were cleaned with a B-R buffer of 10%, v/v, rinsed with H 2 CrO 4 (chromic acid), and washed with distilled water.

Instrumentations and characterization
Field radiation scanning electron microscopy (SEM Model Quanta 250 FEG having 30 kV accelerating voltage with magnification up to 1,000,000) was used for observing the morphological traits and distribution patterns of elements of the materials used in this research, as well as illustrating basic structural and crystallography-ic data of the NCs. The crystallinity of the NCs was also determined with the help of X-ray diffraction (XRD) that worked on the principles of the Bruker D8 framework, which included short curve X-ray scattering (SAXS) and high-resolution diffusion. To acquire data on the functional groups in the investigated samples and capture the Fourier transform infrared (FTIR) spectrum, the JASCO model is employed in a band of 4000-300 cm À1 . The samples were assessed via a Raman spectrometer to ascertain the Raman dimensions (Lab. RAM-HR Evolution Horiba Co., Piscataway, NJ). This included the usage of a solo evident spectrometer fitted with an open air-ventilated electrode 1024 Â 256-pixel CCD detector, a 10% ND filter with an acquisition time of 5 s, a spike-less accumulation filter without delay and 100 objectives, and a 532 nm He-Cd laser. All spectrophotometric assays were evaluated via a quartz cellbased (path width 10 mm) Perkin-Elmer UV-visible spectrophotometer in the frequency range of 190-1100 nm (Lambda 25 model, Los Angeles, CA). Classic B.G. dye is prepared by engaging an automated micropipette (Volac, Sleaford, UK) and pH measurements along with the Orion pH meter (model EA 940), which was used to examine the solutions. The Milli-Q Plus system (Millipore), Bedford, MA, facilitated the preparation of solutions with deionized water. A delicate digital balance ADP 110 L displaying three decimal values was also used in this study.

Preparation of the PTh/ZnO nanocomposites
Two milliliters of thiophene (double distilled were mixed with ZnO NPs (20 wt.%) in 1 M, 100 mL of HCl. The prepared mixture solution was sonicated for half an hour, which was then marked as solution A. Then, in 1 M, 100 mL of HCl and 3 g of total APS was mixed, which was marked as solution B. Later, after cooling, solution B was added dropwise to a mixture of ZnO, NPs, and monomer, for half an hour. The solution was then mixed at 0-4 C with continuous stirring under an atmosphere of nitrogen. The polymerization reaction was withheld under an atmosphere of nitrogen at 0-4 C with continuous stirring for 24 h, and the mixture was refined. The red-colored product obtained was then rinsed numerous times with water DI until the filtered permeate became colorless and was then incubated for 12 h at 50 C. The same steps were repeated without ZnO NPs for preparing pure PTh.

Preparation of the PTh/ZnO/MWCNT nanocomposites
An in-situ polymerization technique was used to produce PTh/ZnO/MWCNT NCs [27]. The distinctive process of preparation is demonstrated as follows: the MWCNTs (10 wt.%) and the ZnO NPs (10 wt.%) were included in a 250.0 mL three-collared flask that contained 100.0 mL 1.0 M HCl; subsequently, 2 mL thiophene (doubly distilled) was added. Then, for half an hour, the obtained mixture was ultrasonicated and cooled in an ice rinse (0-4 C) under constant stirring. A 3.0 g APS solution, which was dissolved in 100.0 mL 1 M HCl, was precooled. The obtained solution was then added dropwise to the above mixture within half an hour (approximately) under an atmosphere of nitrogen at 0-4 C with continuous stirring. Then, the polymerization reaction was maintained for 24 h at 0-4 C under a nitrogen atmosphere with constant stirring. The precipitate formed was then accumulated via ultracentrifugation and rinsed multiple times with water DI until a colorless filtrate was obtained. The fine black powder was dehydrated at 50 C for 12 h to obtain the PTh/ZnO/MWCNT nanocomposites.

Synthesis of ox-MWCNTs
A technique described in the literature was used to develop ox-MWCNTs with utmost care. [28]. MWCNTs (100 mg) were disseminated for 4 h in a mixture of 70% HNO 3 (1:3, v/v) and 96% H 2 SO 4 prior to ultrasonication. Subsequently, the suspension was decayed in an oil bath for 2 h at 80 C with constant stirring. The resultant ox-MWCNTs were diluted with DI water until the pH value of the rinsing solution reached > 5, followed by filtering and drying at 60 C in an oven.

Preparation of the PTh/ZnO/ox-MWCNT nanocomposites
An identical process as 2.4 was employed to prepare PTh/ZnO/ox-MWCNT NCs, although with the use of ox-MWCNTs rather than MWCNTs.

Batch extraction step
An accurate balance between the solid phase (PTh/ ZnO/ox-MWCNT NCs and PTh/ZnO/MWCNT NCs) of exact weight (0.01 ± 0.002 g) and aqueous solution (20 mL) was obtained by incorporating B.G. dye (5 mg L À1 ). The experimental solution was subjected to continuous mechanical stirring for 90 min. After separation of the aqueous phase, the remnants of B.G. dye present in the aqueous phase were measured against the reagent blank via a spectrophotometer [29]. A variation between the absorption of B.G. dye in the liquid phase prior to (A b ) and post (A f ) extraction assisted in determining the quantity of B.G. dye adsorbed on the solid phases (PTh/ZnO/ox-MWCNT NCs and PTh/ZnO/MWCNT NCs). The B.G. dye per unit mass of solid sorbent (mol g À1 ) preserved at equilibrium (q e ), the percentage of sorption (% E), and the dispersion coefficient (K d ) of the sorbed analyte on the solid phased surfaces (PTh/ ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs) were determined as shown. The K d and % E correspond to the aggregate of three self-reliant measurements with the highest accuracy ranging close to ±2%. On the basis of these techniques, the influence of temperature and stirring time on the preservation of the B.G. dyes by the solid phased (PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs) sorbents are assessed.

Sample collection and environmental applications
To assess the B.G. The dye removal and extraction efficacy of solid phase (PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs) sorbent, normal tap water, the water of the Red Sea, and samples of wastewater have been used. The source of tap water was the laboratories of the Chemistry Department at the University of Jeddah, Jeddah City, KSA. Another sample was collected from the Red Sea flowing in Jeddah City, KSA. A wastewater processing plant located at King Abdulaziz University, Jeddah City, KSA, contributed the wastewater sample for this test. The samples were preserved at 5 C in dark Teflon bottles after penetrating a 0.45 lm membranous filter. All three samples were adjusted at pH level 6 along with HCl (0.1 mol L À1 ); simultaneously, solid phases (PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs) were treated with NaOH (0.1 mol L À1 ), after which spectrophotometric measurement of the extracted B.G. dye was performed.

Characterization
The morphological arrangement of the PTh, the binary PTh/ZnO, PTh/ZnO/MWCNTs, and the ternary PTh/ZnO/ox-MWCNTs as derived from SEM and EDX are displayed in Figures 1 and 2. The PTh sample's SEM image, as reflected in Figure  1(a), depicts an inconsistent morphological setup. In contrast, the SEM image of the binary PTh/ZnO has been depicted in Figure 1(b) with an inconsistent morphology. The ZnO NPs have round clusters of inconsistent microcrystals. The uneven shape of the binary NCs resembles the PTh polymer, which reflects that the ZnO NPs are encompassed by polymer chains producing a center-shell configuration similar to the PTh polymer. The ternary SEM image is shown in Figure 1(c), which depicts the ternary PTh/ZnO/MWCNTs SEM image, which demonstrates the potential of MWCNTs as effective templates for polymerization. Polymerized PTh coatings on the exterior layer of ZnO NPs and MWCNTs showed flake-grain-like structural morphology detailed by the homogenous distribution of MWCNTs. The connection between MWCNTs and certain ZnO-NPs, followed by polymer coating through in situ polymerization, can be attributed to these morphological characteristics. The electrostatic p-p Ã electron interplay and hydrogen binding suggested that the development of ternary NCs could have been enhanced, which would ensue in the production of a core-shell-like structure. The addition of ox-MWCNTs in Figure 1(d) alerts the morphology of PTh/ZnO NCs to a bundled shape made up of NPs in collaboration with circular or flat structures comprising ZnO, PTh, and ox-MWCNTs symmetrical pattern. The PTh and ox-MWCNT shells lead to the separation of the cores of ZnO NPs from each other, thus increasing the surface area as well as the capacity of the nanomaterials to distribute evenly in the ternary nanocomposites. In addition, the inclusion of ox-MWCNTs during the polymerization process causes the clustering of PTh and ZnO, owing to the interplay among ox-MWCNTs, PTh, and ZnO NP elements. Figure 2(a) shows the EDX analysis of ternary PTh/ ZnO/MWCNTs NCs, whereas that of ternary PTh/ ZnO/ox-MWCNTs is depicted in Figure 2(b). The existence of maxima attributed to C, S, Zn, and O is verified by Figure 2, thereby confirming the presence of MWCNTs, ox-MWCNTs, PTh, and ZnO in the systems. Figure 3 represents the XRD patterns of diffraction linked to PTh (a), binary PTh/ZnO (b), ternary PTh/ZnO/MWCNTs (c), and ternary PTh/ZnO/ox-MWCNTs (d). Pure PTh's diffraction diagram indicated its amorphous shape, with a tiny peak that arises at 2h of 25 , equivalent to intermolecular l-plate p-p plating [30].  representing the ZnO NP planes. Additionally, the peaks apparent at 2h ¼ 25.40 and 2h ¼ 42.30 showed MWCNTs' diffraction planes at (002) and (100) [32].
The existence of these maxima indicated the synthesis of ternary PTh/ZnO/MWCNTs. Usually, the ternary PTh/ZnO/ox-MWCNTs exhibit the same behavior as the ternary PTh/ZnO/MWCNTs and have comparable diffraction peaks. Nevertheless, the appearance of sharper and increasingly intensive peaks suggests the higher crystallinity of ternary PTh/ZnO/ox-MWCNTs and the systematic structure of the polymer chains of ternary PTh/ZnO/ox-MWCNTs. The coinciding peaks of PTh and NPs lead to crystalline maxima with greater intensity in all NCs. As a result, this increases the long-range combination and enhances p-p interchain piling [33]. The emergence of such peaks also shows the creation of the ternary PTh/ZnO/ox-MWCNT NCs' core-shell layout, as depicted by the SEM photo.
For further clarification of the structure and for determining the chemical composition of freshly produced samples in the category of 400-4000 cm À1 , FTIR spectroscopy has proven to be of great importance. The FT-IR spectra for PTh (a), binary PTh/   Figure  4. The bands appearing in PTh within the 2800-3000 cm À1 range correspond to C-H stretching vibrations [27]. The absorption rings situated at 1438 and 1500 cm À1 signify the C ¼ C symmetrical and asymmetrical stretching vibrations, respectively [34]. The maximum at 825 cm À1 is a typical peak that originates from C-H out-of-plane oscillation of the 2,5-substituted thiophene band formed during the polymerization of thiophene monomers [35]. A unique band at 1069 cm À1 aligns with the in-plane deformity of C-H [36]. In contrast, the absorption ring apparent at 690 cm À1 can be attributed to the C-S bending mode, validating the presence of the thiophene monomer [37]. The Zn-O-Zn ZnO stretch mode crests are visible in the range of 400-500 cm À1 and are shown in the FTIR spectrum of samples of PTh-ZnO, with nearly all of the distinctive bands located in the PTh. However, a mildly reduced peak intensity and a small change in band position are observed after addition to PTh, thus confirming NC creation. Identical peaks were displayed by the PTh/ZnO/MWCNTs and PTh/ZnO; however, the covering of the MWCNTs by the PTh pushed the bands to a slightly lower range, which indicates that PTh and ZnO interact with MWCNTs electronically. The considerable shift of the peak from 690 to 682 cm À1 in line with C-S bending could be linked with the electronic interplay occurring between lone pair electrons of sulfur atoms and p-bonds of PTh/ZnO with p-bonds of MWCNTs. The aforementioned findings resemble trends mentioned in prior studies [38]. The vibrational peaks comparable with ox-MWCNT and ZnO are visible in the IR spectra derived for the ternary PTh/ZnO/ ox-MWCNTs. Moreover, the appearance of all the peaks assigned to PTh shows that the ternary NCs are successfully formed. The FTIR and XRD data have thus proven that ternary NCs are successfully created, can engage in chemical interactions, and possess good crystallinity.
The morphological outlook of the PTh, ZnO NPs, MWCNTs NPs, and ox-MWCNTs NPs was determined by Raman spectroscopy. Figure 5 displays the Raman spectra of PTh (a), binary PTh/ ZnO (b), ternary PTh/ZnO/MWCNTs (c), and ternary PTh/ZnO/ox-MWCNTs (d). The unique peaks displayed by the Raman spectrum of PTh at approximately 1040, 1119, 1424, and 1449 cm À1 correspond to C À H bending, C-C stretching, quinoid form, and C ¼ C stretching, respectively [38]. The binary PTh/ZnO Raman spectra demonstrate that the featured peaks of the ZnO NPs at 433.8 cm À1 are comparable to E2H's basic nonpolar-optical phonon mode of hexagonal wurtzite such as ZnO [31]. The 1 (TO) þ E2 L2L multiphonon scattering modes of metal oxide nanostructures could also be linked to a peak located at 824 cm À1 [39]. Additionally, the maxima representing low-intensity PTh were compared against pure PTh. These properties suggest the effective coating of ZnO NPs by the PTh polymer. Variable peaks visible at 440, 850, 1447,1454, and 1579 cm À1 are described in the Raman spectrum of the ternary PTh/ZnO/MWCNTs. C ¼ C stretching of PTh oscillations in ternary PTh/ZnO/ MWCNTs is attributed to the peak of 1454 cm À1 . The existence of ZnO NPs is marked by peaks located at 440 and 850 cm À1 . The maxima at 1579 cm À1 can be attributed to the MWCNTs' E2 g phonon (G band), whereas the structural flaws (D band) in the MWCNTs account for the peak at 1447 cm À1 [38]. Therefore, the Raman spectra verified that PTh, ZnO, and MWCNTs exist in PTh/ZnO/MWCNTs. The appearance of the typical peaks of D and G of the ox-MWCNTs occurs in the Raman spectrum of the ternary PTh/ZnO/ox-MWCNTs NCs. The G band is characterized by the E2 g mode's in-plane stretching, whereas the D band is triggered by disorders, for example, by sp3-hybridized carbon atoms [40]. The D and G bands of the ox-MWCNTs display Raman spectra of the ternary PTh/ ZnO/ox-MWCNTs at 1342 and 1578 cm À1 , respectively [28]. Moreover, a shift in the PTh ring of the Raman spectrum was observed from 1449 to 1456 cm À1, whereas the Raman spectrum band of ZnO traversed from 433 to 450 cm À1 . The displacement in the bands of the Raman spectrum in PTh and ZnO suggests that the ternary PTh/ZnO/ox-MWCNTs exhibit a strong interaction as defined by charge exchange. Figure 6 shows the comparative analysis of the efficacy of the four polymer NCs in B.G. dye removal from an aqueous phase. The PTh, in addition to PTh/ZnO NCs, ternary PTh/ZnO/MWCNTs NCs, and ternary PTh/ZnO/ox-MWCNT NCs were created and detailed and then utilized for the B.G. dye removal in the aquatic phase ( Figure 6). It was found that the ternary PTh/ZnO/ox-MWCNTs NCs and the ternary PTh/ZnO/MWCNTs NCs were better in dye extraction than other correspondents. As a result, they are chosen as the optimum NCs for all experimental studies.

Adsorption studies
In the aqueous phase, the electronic range of B.G. dye showed an absorption peak at 627 ± 3 nm ( Figure 7). However, thorough stirring of the ternary PTh/ZnO/ox-MWCNTs NCs and the ternary PTh/ZnO/MWCNTs NCs with solid phases remarkably reduced this peak (Figure 7). The effectiveness of the solid phases in removing the B.G. dyes out of   the aqueous phase is confirmed through this behavior.

Retention profile of brilliant green dye from the aqueous solution onto the solid phases
The adsorption and retrieval of heavy metals and dyes are crucially dependent on the pH of the solution. After thoroughly stirring for 90 min, a rigorous evaluation was performed at ambient temperatures of the sorption profile of the aquatic solutions containing B.G. thinners at different pH values by the solid phases of the ternary PTh/ZnO/ox-MWCNTs and the ternary PTh/ZnO/MWCNTs. B.G. The dye concentration in the aquatic phase was determined by photometric recording after attaining equilibrium status [29]. The sorption percentage E for B.G. Dye sorption increases significantly with increasing solution pH until pH 6 in the solid phases of ternary PTh/ZnO/ox-MWCNTs and ternary PTh/ZnO/ MWCNTs NC, which is further reduced with increasing pH beyond pH 6. Descriptive information is displayed in Figure 8. Hence, pH 6 is regarded as the optimal pH value for further studies.
The impact of the mass of the solid phases of ternary PTh/ZnO/ox-MWCNT and ternary PTh/ ZnO/MWCNTs NCs on the proportion of B.G. dye adsorbed via the aqueous solution was determined through the B.G. dye's concentration of 5 mg/L ( Figure 9). The figure shows an increase in the percentage of B.G. dye from 59 to 98%, which was eliminated from the aqueous solution due to the increase in the ternary PTh/ZnO/ox-MWCNTs NCs solid-phase dosage from 5 to 30 mg. A similar incremental trend of the percentage of B.G. dye from 36 to 94% was observed after the increase in the dosage of the ternary PTh/ZnO/MWCNTs NCs solid phase from 5 to 30 mg. This rise in percentage because of the greater number of potential adsorption sites results from increased solid phases.
The connecting period between the adsorbent and adsorbate is a crucial component to the removal of all environmental contaminants via adsorption. The impact of connection time on B.G. dye removal was investigated using ternary PTh/ZnO/ox-MWCNT NCs solid phases in addition to the solid phases of ternary PTh/ZnO/MWCNTs. The findings are provided in Figure 10. This impact was primarily observed in the initial 75 min of adsorption of the maximum proportion of B.G. dye. As displayed in the figure, increasing the connection time leads to a longer adsorption process. The proportion of B.G. dye elimination was equalized within 2 h. This result reflects the dual consecutive-stage process of the adsorption of B.G. dye on the surfaces of solid phases of ternary PTh/ZnO/ox-MWCNTs NCs and PTh/ZnO/MWCNTs NCs, respectively. The first step was the quickest, entailing the transference of B.G. dye to the exterior surface of solid phases from the aqueous phase. The second stage is slower,   spreading B.G. pigments between solid phases. Additionally, the impact of the temperature of the solution on the process of adsorption was examined. A range of four variable temperatures, including 10, 25, 40, and 55 C, were studied. As observed, the rise in solution temperatures from the aforementioned temperature values corresponds to a considerable spike in B.G. dye removal percentage via the solid phases of the ternary PTh/ZnO/ox-MWCNTs NCs and the ternary PTh/ZnO/MWCNTs NCs ( Figure 11). The endothermic characteristic of the adsorption process is proposed by these findings.
The adsorption of dyes is crucially impacted by ionic strength due to its potential to create multiple adsorption circumstances that cause attractive or repulsive interplay between the surfaces of solid phases and dyes. This study highlights the impact of ionic strength on the adsorption process of B.G. dyes on the surface of solid phases (ternary PTh/ZnO/ox-MWCNTs NCs and ternary PTh/ZnO/MWCNTs NCs). The alteration of the ionic strength by using KNO 3 potions of 0.025, 0.05, 0.075, and 0.1 mol/L assisted in conducting the adsorption assessments ( Figure 12). The findings revealed that the proportion of dyes absorbed by the increase in ionic strength in an aqueous phase was somewhat reduced. This may be caused by the fact that the interaction between the surface of adsorbents and dye species is reduced due to cations, such as K þ that cause charges near the surface of the adsorbents [41].

Kinetic behavior of brilliant green dye sorption onto solid phases
The sorption dynamics of contaminants such as B.G. dye from aqueous solution to the solid sorbent holds great import. It offers valuable insights into the steps of the sorption mechanism and reaction processes. The maintenance of B.G. dye sorption on the surface of the solid phases of the ternary PTh/ ZnO/ox-MWCNTs NCs and the ternary PTh/ZnO/ MWCNTs NCs is dependent on film and intramolecular diffusion. The quicker technique of diffusion rules over the total transit rate. The finding was validated by the measurement of B.G. dye sorption half-life (t 1/2 ) from aqueous solutions to solid sorbents under the impact of stirring time. T 1/2 was measured for B.G. dye sorptions using Log C/Co plots against time in solid phases, PTh/ZnO/ox-MWCNT, and PTh/ZnO/MWCNTs. The quantity of t 1/2 for the ternary phases of PTh/ZnO/ox-MWCNTs was 1.74 ± 0.06 min and for ternary PTh/ Zna/MWCNTs 1.43 ± 0.04 and was in accordance with the t 1/2 values reported previously [29]. The film and intraparticle diffusion are therefore liable to determine the kinetics of B.G. dye sorption on solid-phase sorbents. The Weber-Morris model was applied to the solid phases of the ternary PTh/ZnO/ ox-MWCNTs NCs and the ternary PTh/ZnO/ MWCNTs NCs on which the B.G. dye species are adsorbed [29]: (1) q t is the concentration of sorbed B.G. dye at time t, and R d denotes the rate constant of intraparticle transmission. The depiction of q t vs. time is exhibited in Figure 13. The value of R d calculated by the unique slope of Weber-Morris sites ( Figure 13) for the ternary PTh/ZnO/ox-MWCNTs solid-phase stands was 0.667 mg g À1 , with a correlation coefficient (R 2 ¼ 0.993), and was found to be equal for the ternary PTh/ZnO/MWCNTs solid phase at  0.608 mg g À1 with a correlation coefficient ( The kinetic model of the fractional power function, which has been transformed from the Freundlich equation, can be expressed through the following equation [42]: where q t (mg/g) is the quantity of B.G. dye sorbed per unit mass of solid phases, the ternary PTh/ZnO/ ox-MWCNTs, and the ternary PTh/ZnO/MWCNTs at a given time t, while a and b are coefficients wherein b < 1. Application of the formula of the fractional power function to the empirical data of the adsorption process ( Figure 14) brings the data together with correlation coefficient (R 2 ) values of 0.998 and 0.994 for the ternary PTh/ZnO/ox-MWCNTs and the ternary PTh/ZnO/MWCNTs solid phases, respectively, as depicted in Table 1. These figures may indicate the appropriateness of the kinetic model for describing the adsorption of B.G. dye on the solid phases, PTh/ZnO/ox-MWCNTs, and PTh/ZnO/MWCNTs. The Lagergren equation is among the most frequently used equations that describe the adsorption rate of liquid phase systems. The variable sorption of B.G. dye from the aquatic phase to the solid phases, the ternary PTh/ZnO/ox-MWCNTs, and the ternary PTh/ZnO/MWCNTs were dependent on the Lagergren equation [43]: log ðq e Àq t Þ ¼ log q e À k lager t 2:303 where q e denotes the quantity of B.G. dye adsorbed per unit mass of sorbent at equilibrium; k lager is the first-rank aggregate rate constant for the retention technique, and t stands for time. The pattern of log (q e À q t ) vs. time ( Figure 15) was represented as a linear image. The computed values of k lager and q e were found to be equal, that is, 0.036 min À1 and 7.71 mg/g for the ternary PTh/ZnO/ox-MWCNTs solid phase, respectively, with a correlation coefficient R 2 ¼ 0.946. Equal values of 0.039 min À1 and 7.62 mg/g were displayed for the ternary PTh/ZnO/ MWCNTs NCs solid phase, with a correlation coefficient of R 2 ¼ 0.942. However, these data do not follow the first-order kinetics of the B.G. dye species sorption onto the consumed solid-phase sorbent [44]. The pseudo-second rank equation was also understood as a specific category of Langmuir kinetics [45], with the assumption that (i) the concentration of adsorbate is constant over time and (ii) the total number of binding sites depends on the quantity of adsorbate adsorbed at equilibrium. The following equation represents the linear form of the pseudo-second rank rate: where q t and q e denote the quantities adsorbed per unit mass at equilibrium at a given time, and h ¼ k 2 q e 2 can be regarded as the introductory sorption rate. Below such values, the depiction of t/qt vs. t was linear, as illustrated in Figure 16. The intercept and bend for the ternary PTh/ZnO/ox-MWCNTs solid phase are used to determine B.G. dye's equilibrium potential (q e ) and the second-order rate constant (k 2 ) as 4.0 Â 10 À3 g (mg.min) À1 and 9.1 mg/g, respectively, with an extremely good correlation coefficient (R 2 ¼0.989). They were also found to be  equal to 1.9 Â 10 À3 g (mg.min) À1 and 8.3 mg/g, respectively, with the highest correlation value, R 2 ¼ 0.991, in the case of the ternary PTh/ZnO/ MWCNTs solid phase. The data clarify that all the experimental data suitable for large consistency values and pseudo-second-order rate values are constant, commonly depending on experimental circumstances including temperature, pH of the solution, and starting pigment concentration [46].
The Elovich model represents the rate, which is dependent on the adsorption capacity [47]. This model is suitable for chemisorption kinetics and is usually effective for systems with heterogeneous adsorption surfaces. The Elovich model can be described by the following equation: where a (g.mg À1 .min À1 ) implies the initial adsorption rate and b (mg.g À1 .min À1 ) represents the desorption coefficient. The depiction of q t against ln t shows a linear pattern (Figure 17). The a and b criteria of the Elovich model determined for B.G. dye from the intercepts and the slopes of Figure 17 were found to be equal to 0.264 g.mg À1 .min À1 and 1.783 mg.g À1 .min À1 , respectively, and were adsorbed onto the ternary PTh/ZnO/ox-MWCNTs solid phase and were also found to be equal to 0.138 g.mg À1 .min À1 and 1.61 mg.g À1 .min À1 , respectively, adsorbed onto the ternary PTh/ZnO/ MWCNTs solid phase. Of all the kinetic models (Table 1), the pseudosecond-order kinetic model was found to be the most suited kinetic framework to define the adsorption process of B.G. dye by solid phases of the ternary PTh/ZnO/ox-MWCNTs and the ternary PTh/ ZnO/MWCNTs from an aqueous solution.

Comparison with other adsorbents
A comparison of the q e of different adsorbents used in the present work is documented in Table 2. The table itself indicates that the present adsorbent exhibits a   high adsorption capacity toward B.G. dye compared to that of other adsorbents. This indicates that the PTH/ ZnO/ox-MWCNTs NCs have great potential in practical applications for the improved removal of B.G. dye from aqueous solution and industrial wastewater.

Thermodynamic characteristics of brilliant green dye retention onto solid phases
To ascertain B.G. dye retention stages, a wide range of temperatures was studied (298-328 K) in terms of the adsorption of B.G. dyes to solid phases (PTh/ ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs). The thermodynamic criteria (DG, DS, and DH) were predicted with the help of the following equations [53]: where DG, DS, and DH denote the independent energy transformations of Gibbs, free energy, entropy, and enthalpy, respectively. k c stands for the equilibrium constant, R is the gas constant ($8.314 J K 21 mol 21 ), and T is the temperature (in Kelvin). The values of k c for retaining B.G. dye from the experimental aqueous solution at equilibrium on the solid phase sorbents were derived with the equation below:  Figure 18) in the case of the ternary PTh/ZnO/ox-MWCNTs solid phase were found to be 69.0 ± 0.2 kJ mol À1 , 240.3 ± 0.3 J mol À1 K À1 , and À2.6 ± 0.07 kJ mol À1 (at 298 K), respectively. Similar values for the ternary PTh/ ZnO/MWCNTs solid phase were found to be equivalent to 63.2 ± 0.15 kJ mol À1 , 217.0 ± 0.72 J mol À1 K À1 , and À1.5 ± 0.06 kJ mol À1 (at 298 K), respectively. The quantity of DH indicates the endothermic character of the adsorption process in the case of solid phases PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs. The variance in the binding energy between the analyte and sorbent is depicted by this feature. The increase in the extent of freedom at the solid-liquid intercept is proposed by the positive value of DS in the case of solid phases of the PTh/ZnO/ox-MWCNTs and PTh/ZnO/ MWCNTs, which is quite often observed in B.G. dye detention because of the hydration sphere is water molecules releasing amid the processes of   adsorption. Alternatively, the physical and impromptu behavior of B.G. The dye retention on the solid phases of the ternary PTh/ZnO/ox-MWCNTs and the ternary PTh/ZnO/MWCNTs is marked by the negative values of DG at 298 K. Table 3 represents the thermodynamic parameters of the PTh/ZnO/MWCNTs and PTh/ZnO/ox-MWCNTs NCs.

Environmental applications
This study marks the need for real environment samples for investigating the appropriateness of solid phases of PTh/ZnO/ox-MWCNTs and PTh/ ZnO/MWCNTs to eliminate oestrogenic compounds. Three samples of water were gathered for this study, including a water sample from the Red Sea flowing in front of Jeddah City, KSA; a wastewater specimen taken from a treatment plant based at King Abdulaziz University, Jeddah City, KSA; and normal tap water from the Chemistry Department Labs of the University of Jeddah, Jeddah City, KSA. Measurement of B.G. dye's concentration in three samples was found to be lower than the detection limit of UV-vis calculation. After loading the three samples with 5 mg L À1 of B.G. pigments and the addition of PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNT to the solution, they were agitated with 30 mg solid phases at a temperature of 25 C and pH 6 while stirred for almost 2 h. The proportions of B.G. dye obtained from the actual samples of the PTh/ZnO/ox-MWCNTs solid phase were 94.2% for water in the Red Sea, 95.2% for wastewater and 97.7% for tap water and 92.9% for the Red Sea, 94.2% for wastewater, and 96.9 for tap water after loading the samples with 5 mg L À1 of B.G. dye (Figure 19). Regarding the adsorption stability, after using NCs, the NCs were washed with acetone, dried, and then reused with a B.G. dye from the solution. All four cycles exhibited almost a similar percentage of adsorption, which  confirms the capability of reusing and recycling the solid phases of the PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs until multiple adsorption cycles without losing their adsorption efficiency. The NCs have a large surface area due to the presence of sulfur atoms in the polymer and oxygen in zinc oxide (ZnO) as well as in the carbonyl group in ox-MWCNTs. The presence of these active sites increases the surface area of the NCs and thus increases the adsorption efficiency of the dye on the surface of these NCs.

Conclusion
This study entails the production of PTh/ZnO/ MWCNTs, and PTh/ZnO/ox-MWCNTs NCs as innovative adsorbents for organic B.G. dyes through the use of an in situ polymerization technique. The initial production of the NCs was demonstrated by FTIR and Raman tests. The MWCNTs and ox-MWCNTs assist in augmenting the adsorption power of the ternary NCs. A wide range of parameters, such as dye concentration, experimental solution pH, stirring time, and adsorption temperature, were studied. The findings of the adsorption-based experimental studies revealed the B.G. adsorption potential of PTh/ZnO/MWCNTs at 8.3 mg g À1 and PTh/ZnO/ox-MWCNTs at 9.1 mg g À1 , reflecting the strong adsorption power of these NCs (mg/g).