Several industries release varying concentration of dye-laden effluent with substantial negative consequences for any receiving environmental compartment. The control of water pollution and tighter restriction on wastewater discharge directly into the environment to reduce the potential ecotoxicological effect of dyes is forcing processors to retreat and reuse process water and chemicals. Among the different available technologies, the adsorption process has been recognized to be one of the finest and cost-effective wastewater treatment technologies. Various adsorbents have been utilized to remove toxic dyes from water and wastewater. Here, we review the application of polyaniline-based polymeric adsorbent for the adsorption of dyes which have been received considerable attention. To date, various modifications of polyaniline have been explored to improve the adsorption properties. Review on the application of polyaniline for adsorption of dyes has not been present till date. This article provides relevant literature on the application of various polyaniline composites for removing dyes, and their adsorption capacities with their experimental conditions have been compiled. It is evident from the literature survey that polyaniline provides a better opportunity for scientists for the effective removal of various dye.

Application of polyaniline-based adsorbents for dye removal from water and wastewater—a review

A novel polyaniline@Almond shell (PANI@AS) biocomposite was synthesized via facile in situ chemical polymerization method. The as-synthesized adsorbent was characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and potentiometric titration. A batch adsorption system was applied with the aim of investigating as-synthesized adsorbent ability to remove Cr(VI) ions and Orange G (OG) textile dye from aqueous solutions. Obtained results revealed that adsorption process was strongly depended upon the physicochemical parameters. The adsorption of Cr(VI) and OG dye onto PANI@AS was better described by the pseudo second-order-kinetic model and followed the Freundlich isotherm model. The maximum uptakes were 335.25 for Cr(VI) and 190.98 mg g−1 for OG dye. We further evaluated that PANI@AS biocomposite could be regenerated easily with NaOH solution and efficiently reused for Cr(VI) and OG dye removal from aqueous media. Thus, these results indicated the potential practical application of PANI@AS biocomposite for wastewater treatment.

Elaboration of novel polyaniline@Almond shell biocomposite for effective removal of hexavalent chromium ions and Orange G dye from aqueous solutions

Facile synthesis and characterization of a novel 1,2,4,5-benzene tetracarboxylic acid doped polyaniline@zinc phosphate nanocomposite for highly efficient removal of hazardous hexavalent chromium ions from water.

Synthesis and characterization of arginine-doped polyaniline/walnut shell hybrid composite with superior clean-up ability for chromium (VI) from aqueous media: Equilibrium, reusability and process optimization

The current study reports the first use of Fe-ZSM-5 as a potential adsorbent for textile effluent purification. The Fe-ZSM-5 zeolite was synthesized through a hydrothermal method using tetrapropylammonium bromide as an organic structure-directing template for application as a binder for basic Fuchsin (BF) dye from aqueous media. SEM observations confirmed that Fe-ZSM-5 exhibits a granular shape with a quasi-hexagonal structure, which is in agreement with its crystallinity demonstrated by XRD analysis. FTIR analysis indicates the abundance of Si OH groups on the Fe-ZSM-5 surface. N2 adsorption-desorption measurement showed the microporous structure (pore size around 1.93 nm) of Fe-ZSM-5 with a BET surface area of 399 m2/g. The uptake performance of Fe-ZSM-5 zeolite for BF dye was systematically studied as a function of different operational parameters. The experimental adsorption data were in good agreement with pseudo-second-order kinetics and Langmuir isotherm with a maximum adsorbed amount of 251.87 mg/g. BF dye adsorption onto Fe-ZSM-5 was a spontaneous and endothermic phenomenon. The binding mechanism is attributed to electrostatic interactions combined with H-bonding. Further, the response surface modeling permits us to optimize BF dye adsorption process. The highest BF dye removal performance was found to be 99.6 % under optimum conditions of pH 5, Fe-ZSM-5 dose 0.75 g/L, initial BF concentration 10 mg/L for 120 min at 20 °C. The findings of this work revealed that Fe-ZSM-5 zeolite could be proposed as an alternative adsorbent with outstanding performance for BF dye removal from wastewaters.

Fe-ZSM-5 zeolite for efficient removal of basic Fuchsin dye from aqueous solutions: Synthesis, characterization and adsorption process optimization using BBD-RSM modeling

Synthesis and characterization of polyaniline-based biocomposites and their application for effective removal of Orange G dye using adsorption in dynamic regime

The polypyrrole (PPy) was used as an adsorbent material for efficient removal of pharmaceutical metronidazole from aqueous solutions. The physiochemical parameters influencing the adsorption process such as adsorbent dose, temperature, pH, initial concentration and contact time were systematically investigated. The optimum adsorption efficiency is achieved at pH 6.17 after 120 min of contact time. In addition, the Langmuir isotherm and pseudo-second-order models were found to explain the metronidazole adsorption process on the PPy. The thermodynamic parameters indicate that the adsorption of metronidazole on the PPy is a spontaneous and exothermic process. The quantum calculations using density functional theory (DFT) was used to confirm the adsorption mechanism of metronidazole on the PPy. The obtained results of the interaction energy indicate that the adsorption was a physical process. The metronidazole was adsorbed by its oxygen atoms on the amine groups of PPy. Finally, the PPy polymer can be used as an efficient adsorbent for removal of pharmaceutical pollutants from wastewater.

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Experimental and DFT studies of the removal of pharmaceutical metronidazole from water using polypyrrole

The polypyrrole composite filled with a cellulosic agricultural waste ( Nut-shells of Argan ) was prepared by chemical oxidative polymerization. PPy/ Nut-shells of Argan (PPy/NA) composite was used as an eco-friendly adsorbent for the removal of three polycarboxy-benzoic acids (hemimellitic, trimellitic, and pyromellitic acids) from single, binary, and ternary systems. The effects of parameters influencing the adsorption process including initial pH, adsorbent dose, contact time, initial concentration of polycarboxy-benzoic acids, and temperature were investigated. The kinetics studies indicated that the pseudo-second-order kinetic model well better described the adsorption kinetics for single systems. The adsorption equilibrium data from single, binary, and ternary systems were successfully described by the Langmuir isotherm model. The comparison of equilibrium adsorbed amounts in single and multi-component systems shows an antagonism effect. The obtained results indicate that the affinity of studied polycarboxy-benzoic acids on the surface of PPy/NA composite followed the order pyromellitic acid > trimellitic acid > hemimellitic acid. The thermodynamic parameters show that the nature of adsorption is spontaneous and endothermic.

Simultaneous removal of benzene polycarboxylic acids from water by polypyrrole composite filled with a cellulosic agricultural waste

Adsorbents in the form of powders are commonly used to filtrate organic compounds in waters. However, this technique requires the separation of the solid phase from the solution after adsorption experiments. Here we propose the use of films as adsorbents. We synthesized polyaniline films by chemical oxidative polymerization of aniline on red ceramic brick. This film was tested to remove trimellitic, hemimellitic and pyromellitic acids as model molecules of the biodegradation of aquatic humic substances. We evaluated the effect of pH, contact time and initial concentration. Our results show that optimal adsorption conditions required 45 min of solid/liquid contact at pH 7 and an initial concentration of 20 mg/l. The maximum adsorption capacities for hemimellitic, trimellitic and pyromellitic acids are 154.83 for hemimellitic acid, 161.88 for trimellitic acid and 175.26 mg/g for pyromellitic acid. The adsorption efficiency of the polyaniline film decreased only by 13 % after four cycles. Overall, we conclude that polyaniline films are promising separable adsorbents compared to conventional adsorbents for removal of aromatic polycarboxylic acids from water.

Polyaniline films for efficient removal of aromatic acids from water

The adsorption of trimellitic and pyromellitic acids has been performed onto synthesized polyaniline (PANi) by chemical oxidative polymerization. Different parameters that influence the adsorption processes (pH, temperature, ratio solid/liquid, initial concentration, and contact time) had been examined. Adsorption kinetic study indicates a great adjustment with pseudo-second-order kinetic model. The equilibrium data were best fitted by Langmuir isotherm model. The maximum monolayer adsorption capacities are 67.4 and 94.5 mg/g for trimellitic and pyromellitic acids, respectively. Comparison of the adsorption capacities indicates that increasing the number of carboxylic functional groups promotes adsorption on the PANi. Thermodynamic parameters (ΔH°, ΔS°, and ΔG°) indicate that the adsorption is spontaneous and endothermic in nature. The calculations of chemical quantum parameters were performed for optimized molecular structures using the AM1 and MINDO semi-empirical methods. The theoretical data w...

Hassan Kabli

Papers

Synthesis and characterization of polyaniline-based biocomposites and their application for effective removal of Orange G dye using adsorption in dynamic regime

Experimental and DFT studies of the removal of pharmaceutical metronidazole from water using polypyrrole

Simultaneous removal of benzene polycarboxylic acids from water by polypyrrole composite filled with a cellulosic agricultural waste

Polyaniline films for efficient removal of aromatic acids from water

Experimental and theoretical studies on the removal of polycarboxy-benzoic acids by adsorption onto polyaniline from aqueous solution