Removal Of Toxic Dyes Research Articles

Agar based bimetallic nanoparticles as high-performance renewable adsorbent for removal and degradation of cationic organic dyes

Removal of toxic organic compounds from the industrial wastewater is currently one of the most important subjects in water pollution control. A highly efficient, effective and rapid polysaccharide (agar)-based adsorbent was synthesized by modifying monometallic/bimetallic nanoparticles (Fe, Cu, Pd, Fe/Cu and Fe/Pd) to remove cationic dyes (methylene blue, MB and rhodamine B, RhB). The effects of different parameters like initial contact time, solution pH value, temperature and amount of adsorbent on the adsorption capacity as well as dye removal capacity of the adsorbent were investigated. The maximum adsorption capacities of the agar@Fe/Pd nanoparticles based adsorbent for both MB and RhB were found 875.0mgg−1 and 780.0mgg−1, respectively. On the optimized parameter, the adsorbent shows a very high efficiency and rapid removal property for both the dyes. The adsorption follows the Freundlich isotherm model for the equilibrium process. The kinetic studies revealed that the adsorption of both the dyes followed the pseudo-first order kinetic model. Additionally, two different models, i.e. intraparticle diffusion and elovich model were also studied for adsorption of both the dyes. Similarly, the rate of degradation of MB and RhB on agar@Fe/Pd nanoparticles was also studied and their rate constants were found as 3.16×10−2s−1 and 4.82×10−2s−1, respectively. Furthermore, the regeneration experiments showed that the adsorbent could be reused for at least 20 cycles with very efficient dye removal capacity (90%) even in complex systems containing mixture of dyes, salt, and surfactant. Thus, the agar-based adsorbent has the potential in the fast and effective adsorption, removal and degradation of toxic dyes from industrial textile wastewater.

Enhanced removal of toxic Congo red dye using multi walled carbon nanotubes: Kinetic, equilibrium studies and its comparison with other adsorbents

MWCNTs were used as an efficient adsorbent for rapid removal of hazardous Congo red dye (CR) from aqueous solutions; the whole adsorption process was well investigated and elucidated. The impact of several significant parameters such as contact time, pH, temperature and initial concentration were well studied and optimized. As a result of optimization the values of influential parameters such as contact time, pH, temperature, initial concentration and fixed adsorbent dose were found to be 60min, 11, endothermic, 200ppm and 0.05g, respectively. The developed nano adsorbent shows an excellent potential (qe, 352.11mg/g; 92% of CR has been removed within 60min) for removal of CR from the solvent phase. The adsorption kinetics and isotherm data were found to be well fitted and in good agreement with the pseudo-second order and Langmuir isotherm models, respectively. The efficient and rapid removal of the noxious CR dye using MWCNTs in a very short period of time, and the obtained maximum adsorption capacity of the developed adsorbent in comparison to the previously developed adsorbent establishes the significance of the work done.

Selective removal of toxic anionic dyes using a novel nanocomposite derived from cationically modified guar gum and silica nanoparticles

A novel nanocomposite derived from cationically modified guar gum and in-situ incorporated SiO2 NP (cat-GG/SiO2) has been developed. The cat-GG has been synthesised by grafting poly(2-(diethylamino)ethyl methacrylate) on GG backbone. Various analyses endorse the suitability of cat-GG as well-organized template for the development of homogeneous SiO2 NPs. Dye adsorption studies predict that cat-GG/SiO2 efficiently and selectively adsorb anionic dyes (reactive blue—RB and Congo red—CR) from mixture of dye solutions. This is because of high surface area, multifunctional chelating H-bonding interactions and electrostatic interactions of cationic adsorbent with anionic dyes. Dyes adsorbed on the composite surface are desorbed reversibly using pH 10 stripping solution. Besides, cat-GG/SiO2 has been recycled efficiently with no prominent loss of dye uptake capacity, even after 4 adsorption–desorption cycles.

Characterization of reactive amphiphilic montmorillonite nanogels and its application for removal of toxic cationic dye and heavy metals water pollutants

The present work aims to reduce the water surface tension using dispersed organophilic clay minerals to increase the adsorption water pollutants (organic and inorganic) into the clay galleries. Therefore, sodium montmorillonite (Na-MMT) was functionalized with amphphiles based on crosslinked nanogel polymers of N-isopropylacrylamide (NIPAm), sodium 2-acrylamido-2-methylpropane sulfonate (Na-AMPS), acrylamide (AAm) and acrylamidopropyl)trimethylammonium chloride solution (APTAC) using surfactant free technique. The chemical interactions between nanogels and Na-MMT and their chemical structure were confirmed by FTIR analysis. The intercalation and exfoliation of Na-MMT were confirmed by wide-angle X-ray diffraction. The morphology of Na-MMT nanogel composites was investigated by TEM analysis. The adsorption capacities of the prepared Na-MMT nanogels for methylene blue dye, cobalt and nickel cations from water were investigated. The data indicated that the Na-MMT nanogels reduced the surface tension of water and efficiently remove dye and metal ions from water.

Cranberry Stem as an Efficient Adsorbent and Eco-Friendly for Removal of Toxic Dyes from Industrial Wastewater, Physico Studies

The adsorption of Congo red (CR) from aqueous solution using treated ground cranberry stem by varying the parameters such as contact time, dye concentration, adsorbent dose, pH and temperature was investigated. Adsorption isotherms of CR onto CS were analyzed by Langmuir and Freundlich. It was observed that the optimum CR adsorption onto ground CS occurred at contact time of 30 minutes, the adsorbent dosage of 8 g, initial concentration of 50 mg/L and pH 2. In addition, the particle size of ground CS has no significant effect on the adsorption of CR. Adsorption isotherms studied through the use of graphical methods revealed that the adsorption of CR onto cranberry stem follows both Langmuir and Freundlich models, with the maximum adsorption capacity was 95.25mg g-1. The ground cranberry stem investigated in this study thus exhibited as a high potential adsorbent for the removal of CR from aqueous solution.

High-value utilization of egg shell to synthesize Silver and Gold–Silver core shell nanoparticles and their application for the degradation of hazardous dyes from aqueous phase-A green approach

The common household material, egg shell of Anas platyrhynchos is utilized for the synthesis of Silver and Gold–Silver core shell nanoparticles using greener, environment friendly and economic way. The egg shell extracts were acting as a stabilizing and reducing agents. This method avoids the use of external reducing and stabilizing agents, templates and solvents. The effects of various reaction parameters, such as reaction temperature, concentration in the formation of nanoparticles have also been investigated. The compositional abundance of gelatin may be envisaged for the effective reductive as well as stabilizing potency. The mechanisms for the formation of NPs have also been presented. The synthesized Ag NPs formed were predominantly spherical in nature with an average size of particles in the range of 6–26nm. While, Au–Ag core shell nanoparticles formed were spherical and oval shaped, within a narrow size spectrum of 9–18nm. Both the Ag NPs Au-and Ag core shell nanoparticles showed characteristic Bragg’s reflection planes of fcc structure and surface plasmon resonance at 430nm and 365nm, respectively.The NPs were utilized for the removal of toxic and hazardous dyes, such as Rose Bengal, Methyl Violet 6 B and Methylene Blue from aqueous phase. Approximately 98.2%, 98.4% and 97% degradations of Rose Bengal, Methyl Violet 6 B, and Methylene Blue were observed with Ag NPs, while the percentage degradation of these dyes was 97.3%, 97.6% and 96% with Au–Ag NPs, respectively. Therefore, the present study has opened up an innovative way for synthesizing Ag NPs and Au–Ag bimetallic nanostructures of different morphologies and sizes involving the utilization of egg shell extract. The high efficiency of the NPs as photocatalysts has opened a promising application for the removal of hazardous dyes from the industrial effluents.

Solvent free synthesis of ZnO nanostructures and evaluation of their capability for water treatment

ZnO hexagonal disks were successfully synthesized using mechanochemical reaction followed by heating treatment. Urea was used as a complexing and directing agent to produce precursor, namely, [Zn(CO(NH2)2)·(NO3)2]·3(H2O). The as-synthesized product indicated a pure and uniform morphology of hexagonal-based disks with the average thickness of 52nm and high aspect ratio of 96. The change of some reaction conditions was led to generate timber-like and particulate structures. The structural and morphological characteristics of all samples were also discussed in detail. In addition, the batch studies were carried out to evaluate the capability of the prepared products for the removal of toxic dyes like Brilliant green and Malachite green, the industry wastes, using adsorption process with a post-photocatalytic treatment. The results showed the hexagonal disks and timber-like nanostructures are the efficient decolorizing adsorbents for water treatment by both of adsorption and photocatalytic pathways. Although the value of maximum adsorption capacity was good, the photocatalytic degradation indicated a superior removal efficiency of dye pollutants on the prepared ZnO nanostructures.

Direct synthesis of mesoporous molecular sieves of Ni-SBA-16 by internal pH adjustment method and its performance for adsorption of toxic Brilliant Green dye

An ordered mesoporous novel material Ni-SBA-16 has been synthesized by internal pH-adjustment method. The synthesized material has been characterized by small angle XRD (SXRD), wide angle XRD (WXRD), Scanning Electron Microscope (SEM), High-Resolution Transmission Electron Microscope (HRTEM), Fourier-transform Infra-red (FTIR) spectroscope and Nitrogen Adsorption desorption techniques. The characterization results have shown that material possesses highly ordered mesostructure with high surface area (736m2/g) and large pore diameter (3.8nm). FTIR and WXRD spectra revealed that nickel was uniformly dispersed on SBA-16 surface. The synthesized material has been used as adsorbent for removal of toxic Brilliant Green dye due to its large surface area and pore size. At optimized conditions, almost 100% of Brilliant Green dye was removed from aqueous solution by Ni-SBA-16. The isotherms analysis indicates that the Langmuir and Hill models provide the best correlation of the experimental data. The maximum adsorption capacity (qmax) of Ni-SBA-16 for Brilliant Green dye was 322.58mg/g.

MgO nanomaterials with different morphologies and their sorption capacity for removal of toxic dyes

MgO nanorods, hierarchical nanostructures and nanoflakes were synthesized by precipitation, reflux and hydrothermal methods, respectively. The SEM and FESEM images suggested the formation of nanorods with diameter around 400–500nm, hierarchical nanostructures containing plates with thickness around 100–200nm and nanoflakes with diameter around 300–500nm. XRD and FTIR confirmed the formation of single phase MgO with well crystalline nature. The hierarchical MgO nanostructures possessed higher specific surface area (147.5m2/g) than MgO nanorods (48.45m2/g) and nanoflakes (110.9m2/g). The prepared nanomaterials were used as adsorbents to remove organic dyes such as Malachite green and Congo red from aqueous media. The percentage of removal of Malachite green by MgO nanorods, hierarchical nanostructures and nanoflakes are 95.1, 99.98 and 97.42%, respectively, and percentage of removal of Congo red by MgO nanorods, hierarchical nanostructures and nanoflakes are 86.28, 99.94 and 92.68%, respectively. The hierarchical MgO nanostructure exhibited excellent adsorption performance for removal of Malachite green and Congo red with maximum sorption capacities of 1205.23 and 1050.81mg/g, respectively.

Polyacrylamide/Ni0.02Zn0.98O Nanocomposite with High Solar Light Photocatalytic Activity and Efficient Adsorption Capacity for Toxic Dye Removal

Photocatalytic removal of toxic textile dyes from wastewater is a challenge because of the relatively low efficiency of photocatalysts. There has been sustained interest in a variety of cheap, hybrid, and efficient nanomaterials for wastewater treatment. In the present work, a novel photocatalyst polyacrylamide/Ni0.02Zn0.98O (PAM/NZP) was synthesized successfully by addition of nanoparticles during polymerization of acrylamide in aqueous medium using ammonium persulfate and N,N′-methylenebis(acrylamide). The material possesses excellent photoactivity and high adsorption capacity.The present investigation describes the applicability of PAM/NZP for removal of malachite green (MG) and rhodamine B (RB) from aqueous solution. The effect of adsorption capacity of cross-linked polyacrylamide on photocatalytic activity of Ni0.02Zn0.98O was also studied. The materials were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, small area electron diffraction, thermal gravimetric analysis, and ultraviolet–visible spectroscopy. The optical band gap was 3.17 eV for NZP and 3.07 eV for PAM/NZP, which is quite lower than that of bare ZnO. The simultaneous adsorption and photocatalysis proved to be a better reaction condition for photodegradation of both the dyes in the presence of PAM/NZP under natural sunlight irradiation. A significant removal efficiency of 99.17% for RB and 96.55% for MG was achieved in 2 h of solar illumination in the presence of the nanocomposite. In addition, the nanocomposite has a high recycling efficiency.

Lithium dodecyl sulphate assisted synthesis of Ag nanoparticles and its exploitation as a catalyst for the removal of toxic dyes

We established for the first time the dual significance of lithium dodecyl sulphate (LDS) as a reducing agent as well as a stabilizing agent in the synthesis of silver nanoparticles (Ag NPs). This is an eco-friendly and economical method which avoids the utilization of additional external reducing agent, external stabilizing agent, template and solvent. The size and morphology of the individual Ag NPs can be tuned by controlling the various reaction parameters, such as temperature, concentration and pH. The studies showed that with increase in concentration, not only the size but also the morphology of the Ag NPs changes (from particles to rod). The size of the Ag NPs increased with increase in temperature and pH. The prepared Ag NPs were characterised by ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) analyses. The probable mechanism for the formation of Ag NPs is presented. The formation of Ag NPs was also studied as a function of time. The synthesised Ag NPs were used for the catalytic reduction of methylene blue and eosin dyes in aqueous media and methylene blue in micellar media. They exhibited good catalytic reduction ability towards methylene blue and eosin dyes in aqueous and micellar media. The probable mechanism for the reduction of dyes is also presented in this article.

A novel gel-based approach to wastewater treatment – unique one-shot solution to potentially toxic metal and dye removal problems

This communication reports the development of a unique gel-based adsorbent for wastewater treatment using a new low molecular weight gelator. The most interesting aspect of this technique is that the ligand not only gelled potentially toxic metals, like lead and cadmium, but that it also simultaneously adsorbed toxic dyes, like methyl orange, from an aqueous solution. This offers a one-shot solution to two major water purification problems.

Effective biodecolorization potential of surface modified lignocellulosic industrial waste biomass

Abstract The biosorption ability of sugar-beet pulp was improved by modifying with quaternary ammonium-salt for examination of its potential application in decolorization process from wastewater. Decolorization conditions were investigated as functions of different experimental parameters such as initial pH, biosorbent amount, time and dye concentration. At the optimum pH (2.0) the biosorption reached to an equilibrium within relatively short time (30 min) and was followed by the pseudo-second-order kinetic model. Langmuir isotherm better fitted the equilibrium data with the maximum monolayer biosorption capacity of 98.32 mg g−1. AR1 biosorption performance of quaternary ammonium-salt modified sugar-beet pulp (QAMSBP) was also investigated in the mix solutions containing RB49 and AY17 dyes at different concentrations (1, 50 and 100 mg L−1) and the biosorption potential of QAMSBP did not change at 1 and 50 mg L−1 of other dyes. Obtained results demonstrated that AR1 biosorption onto QAMSBP could also be successfully applied to real wastewater in continuous system. IR analysis revealed the complexation is one of the important mechanisms involved in AR1 biosorption. All the results indicated that QAMSBP was a potential biosorbent for toxic dye removal from wastewaters.

Enhancing adsorption capacity of toxic malachite green dye through chemically modified breadnut peel: equilibrium, thermodynamics, kinetics and regeneration studies

Breadnut skin, in both its unmodified (KS) and base-modified (BM-KS) forms, was investigated for its potential use as a low-cost adsorbent for the removal of toxic dye, malachite green (MG). Characterization of the adsorbents was carried out using scanning electron microscope, X-ray fluorescence and Fourier transform infra-red spectroscopy. Batch adsorption experiments, carried out under optimized conditions, for the adsorption of MG were fitted using five isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Sips) and six error functions to determine the best-fit model. The adsorption capacity was greatly enhanced when breadnut skin was chemically modified with NaOH, leading to an adsorption capacity of 353.0 mg g−1, that was far superior to most reported adsorbents for the removal of MG. Thermodynamics studies indicated that the adsorption of MG was spontaneous on KS and BM-KS, and the reactions were endothermic and exothermic, respectively. Kinetics studies showed that both followed the pseudo-second order. Regeneration experiments on BM-KS indicated that its adsorption capacity was still maintained at>90% even after five cycles. It can be concluded that NaOH-modified breadfruit skin has great potential to be utilized in real-life application as a low-cost adsorbent for the removal of MG in wastewater treatment.

Comparison of physico-chemical, advanced oxidation and biological techniques for the textile wastewater treatment

Toxic organic dye removal from the textile wastewater is a serious concern. It is difficult to choose a single or a combination of treatment techniques between various available options; each with certain advantages and drawbacks. Six different techniques were applied on the same textile wastewater to evaluate the most effective in terms of treatment efficiency. The three most important textile wastewater quality parameters of chemical oxygen demand (COD), total suspended solids (TSS) and color were made the basis of the comparison of different treatment techniques. Other critical parameters such as treatment time, ease of operation and chemical cost employed were also considered. No single biological or physico-chemical treatment technique was found capable of removing up to 80% of the influent COD, TSS and color simultaneously from the textile wastewater. The conventional activated sludge (CAS) treatment followed by effluent polishing with the sand filtration (SF) and activated carbon adsorption columns was proved to be the most promising with COD, TSS and color removal efficiencies of 81.6%, 88.5% and 94.5% respectively. Moreover this combination of techniques enjoys lower chemical cost, medium operation time and fewer difficulties in the process control. Hence, the combination is recommended for the treatment of the textile effluents.

Magnetite decorated multi-walled carbon nanotubes for removal of toxic dyes from aqueous solutions

The removal of malachite green (MG) and rhodamine B (RB) from aqueous solutions was studied by batch adsorption technique using Fe3O4/MWCNT. Fe3O4/MWCNT adsorbent was synthesized by co-precipitation method and characterized by XRD, SEM, and TGA. 94 % MG removal and 98 % RB removal were achieved in 80 min using 10 mg adsorbent, at pH 6 and 298 K. The effects of adsorbent amount, pH, initial dye concentration, contact time, and temperature were investigated. Equilibrium data were well fitted by Langmuir adsorption model and pseudo-second-order kinetic model. MG adsorption on Fe3O4/MWCNT is exothermic and RB adsorption is endothermic in nature.

Polyaniline‐functionalized magnetic nanoparticles for the removal of toxic dye from wastewater

ABSTRACTA novel and inexpensive approach was adopted to develop a magnetic nanocomposite for the adsorption of cationic dye from an aqueous solution. This nanocomposite, which was based on a superparamagnetic iron oxide nanocore, was functionalized with a hydrophilic coating of polyaniline (PANI). The nanoparticle size, colloidal stability, surface chemistry, and magnetic properties were studied extensively by transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The polymeric functionalized magnetic nanocomposite had an average core size of 20–40 nm and a shell size of 6–10 nm. To evaluate the potential of such nanocomposites for dye adsorption, malachite green (MG) was exposed with different operational parameters, such as the pH, temperature, initial concentration of the dye, contact time, and reusability. The rate of the adsorption followed pseudo‐second‐order kinetics with the adsorption isotherm fit the Langmuir isotherm model well. The maximum adsorption capacity was 240 mg of MG/g of adsorbent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40840.

Efficient removal of malachite green dye using biodegradable graft copolymer derived from amylopectin and poly(acrylic acid)

This article reports on the application of a high performance biodegradable adsorbent based on amylopectin and poly(acrylic acid) (AP-g-PAA) for removal of toxic malachite green dye (MG) from aqueous solution. The graft copolymer has been synthesized and characterized using various techniques including FTIR, GPC, SEM and XRD analyses. Biodegradation study suggests that the co-polymer is biodegradable in nature. The adsorbent shows excellent potential (Qmax, 352.11mgg−1; 99.05% of MG has been removed within 30min) for removal of MG from aqueous solution. It has been observed that point to zero charge (pzc) of graft copolymer plays significant role in adsorption efficacy. The adsorption kinetics and isotherm follow pseudo-second order and Langmuir isotherm models, respectively. Thermodynamics parameters suggest that the process of dye uptake is spontaneous. Finally desorption study shows excellent regeneration efficiency of adsorbent.

Adsorptive removal of toxic dye from aqueous solution and real industrial effluent by tris(2‐aminoethyl)amine functionalized nanoporous silica

Ordered nanoporous silica SBA‐15 was successfully synthesized and functionalized by tris(2‐aminoethyl)amine (Tren), a multi‐amine ligand, to develop efficient cationic dye adsorbent. The prepared materials were characterized by XRD, N2 adsorption–desorption, TGA, and FT‐IR analysis. Tren‐SBA‐15 was used for the removal of malachite green (MG) from both aqueous solution and real textile effluent. The effects of various operational parameters including solution pH, adsorbent dosage, contact time, initial concentration and temperature on removal of MG using Tren‐SBA‐15 were investigated in batch adsorption mode. Within the optimum conditions, Tren‐SBA‐15 exhibited an excellent adsorptive capability of 2330 m g−1 (6.38 mmol g−1) with removal of 89.8%. Equilibrium data was best described by the Freundlich and Sips isotherm models indicated a favorable adsorption process (nF > 1) and heterogeneous system for dye adsorption (nS > 1). The adsorption kinetic behavior was influenced by intraparticle diffusion and pseudo‐second‐order kinetic model provided well‐fitted to the experimental data. The kinetic rate constant increased with temperature. Qualitative estimates of the thermodynamic parameters showed that the overall adsorption process is spontaneous (ΔG < 0) and a bit endothermic (ΔH > 0), and adsorption mechanism was assumed to be a physisorption. Experiment with real textile wastewater showed 48.7% MG removal by the use of 0.01 g Tren‐SBA‐15. The reusability of the adsorbent in real wastewater was shown to be successful along with its regeneration possibility. Desorption experiments were performed by two deferent eluents to desorbs both cationic ions and dye molecules from Tren‐SBA‐15. The results showed that dye is removed completely from real effluent after two continues adsorption/desorption cycles. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1242–1250, 2014

Synergistic Effect of Chitosan and Titanium Dioxide on the Removal of Toxic Dyes by the Photodegradation Technique

The photodegradation of three different types of dyes like an anionic dye, a cationic dye, and a zwitterionic dye, namely, Reactive Red 2 (RR), Methylene Blue (MB), and Rhodamine B (RB), respectively, have been carried out using chitosan/TiO2 composite (CTC). The as-synthesized CTC was characterized by Fourier transform infrared (FTIR) spectral studies, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), BET, X-ray diffraction (XRD), and thermal analysis (thermogravimetric analysis (TGA) and differential thermal analysis (DTA)). The enhanced photocatalytic activity of CTC for the degradation of the dyes was attributed to the synergistic effect of TiO2 and chitosan (CS). The photodegradation experiments were carried out by varying different parameters such as irradiation time, dosage, pH, initial dye concentration, coexisting ions, hydrogen peroxide, and light intensity. The kinetic behavior was described in terms of the Langmuir–Hinshelwood model. The confirmation of mineraliza...