Removal Of Eriochrome Black T Research Articles

Phycoremediation of Phenolphytalein, Indigo Carmine, Methyl Orange and Eriochrome Black T By Using Chlamydomonas and Chlorella sp. (Chlorophyta)

This work aimed to evaluate the decolorization of phenolphthalein (PP), indigo carmine (IC), methyl orange (MO) and eriochrome black T (EBT) by using Chlorella and Chlamydomonas as a biosorbent. This experiment used the batch adsorption method to study the adsorption effect of pH, biomass dosage, contact time, initial dye concentration and temperature on the dyes. The adsorption of the dyes onto the cells were fitted with the Langmuir and Freundlich isotherms. The results showed that the optimum conditions for PP removal (99%) was obtained at pH 4, contact time of 120min, 35°C, algal dosage of 0.5 mg/mL and dye concentration of 100 mg/L on to the cells. The sample prepared at 25°C, 120 min, 1 mg/mL algal dosage, 25 mg/L dye concentration and at pH 4 had the best adsorption effect on IC on to the both of cells (99-98%). In addition, the optimum conditions for MO and EBT removal (99-97%) was obtained at pH 2-4, contact time of 30 min, 25°C, algal dosage of 0.5mg/mL and dye concentration of 100mg/L. The results of this study reveal that the algae cells can be utilized as an efficient and eco-friendly biosorbent for the removal of the indicator dyes from aqueous solution.

Composite electrospun membranes based on PET-PAN modified with LDH-hybrid as promising adsorbent for pollutants removal from wastewater

<p>The current work reveals the fabrication of a novel nanofiber composite membrane of PET-PAN modified with Mg-Al-LDH-PVA through electrospinning process. The nanocomposite membranes characterization was conducted with different techniques i.e. SEM, EDS, FTIR, XRD, and water contact angle to evaluate the structure and surface morphology. The optimized nanomembrane was utilized as a useful adsorbent for removal of toxic anionic dye Eriochrome Black T (EBT) and cationic dye Methylene blue (MB) from wastewater. Experimental results identified that PPLP3 membrane has a potential for the removal of EBT (83%) and MB (52%) at pH 3 and 7, respectively, from aqueous solution. The optimum adsorption capacity of PPLP3 nanocomposite membrane was identified and calculated as 7.3 mg.g-1 followed by the pseudo 2nd order kinetics and Langmuir adsorption isotherm fit well with R2 values of 0.964 and 0.997, respectively. The synthesized nanocomposite membrane could be utilized for effective adsorption of contaminations from different wastewaters.</p>

Polypyrrole-encapsulated metal oxide nanocomposite for adsorptive abatement of anionic dye from dye laden wastewater: Cost analysis and scale up design

The present work demonstrates the fabrication of an organometallic material i.e. polypyrrole-encapsulated zinc oxide (PPy@ZnO) nanocomposite for adsorptive elimination of Eriochrome black-T (EBT) dye from water. The specific surface area and pore volume of the PPy@ZnO nanocomposite were observed to be 28.726 m2/g and 0.086 cc/g, respectively. At optimum experimental conditions of solution pH; 4.0, PPy@ZnO nanocomposite dose: 1.0 g/L, contact time: 30 min and initial EBT dye concentration: 50 mg/L, maximum EBT dye removal efficiency of ∼94±1.86% was obtained. The pseudo-second-order kinetic and Langmuir isotherm model provides the best fit for the adsorption experiments, with maximum EBT dye adsorption capacity of 277.78 mg/g. The prominent adsorption mechanisms include the hydrogen bonding, π–π interactions, and electrostatic attraction. The adsorption study is spontaneous (ΔG° < 0) and endothermic (ΔH° > 0, ΔS° > 0) in nature as indicated by the thermodynamics study. The reduction in EBT dye removal efficiency was insignificant (∼10±0.94%) in surface water as compared to other real water samples. Monovalent anions (i.e., NO3–and Cl–) have minimal impact on EBT removal efficiency with reduction in removal efficiencies in the range of 4.0±1.54% to ∼11.0±1.93%. Regeneration study suggests an overall ∼20±1.45% decrease in the EBT dye removal efficiency after 5th cycle of regeneration. Response surface methodology suggests the maximum adsorption efficacy of 95±1.68% at initial EBT dye concentration of 35 mg/L, PPy@ZnO dose of 0.85 g/L and contact time of 40 min. The estimated synthesis cost of PPy@ZnO nanocomposite was determined to be ∼117 USD/kg. Batch mode scale-up design suggests a minimum of 87.48 g of PPy@ZnO nanocomposite needs to be applied to treat 50 mg/L of EBT dye loaded wastewater (50 L volume) with 95% dye removal efficiency.

Removal of Eriochrome black-T from wastewater by utilizing the commercial DF-120 anion exchange membrane

This work describes the batch adsorption of Eriochrome black-T (EBT) an anionic dye onto the DF-120 commercial anion exchange membrane (AEM) from wastewater at 25 °C. The effect membrane dosage, temperature, ionic strength, contact time, pH and initail concentration on EBT adsorption was illustrated. Adsorption capacity (qe) was enhanced from 7.32 to 12.71, 1.77 to 12.71, 6.71 to 12.71, and 16.16 to 17.39 mg/g with membrane dosage (mass), initial concentration, contact time, and ionic strength respectively while decreased from 12.71 to 3.77 and 12.71 to 3.65 mg/g with temperature and pH of medium respectively. Adsorption of EBT was subjected to various adsorption isotherms including Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) models. It was noticed that EBT adsorption obeyed Freundlich isotherm because the value of correlation coefficient (R2 = 0.991) was close to unity. Several kinetics models were utilized to demonstrate EBT adsorption. Results showed that EBT adsorption fitted to pseudo-second order (PSO) model because the value of correlation coefficient (R2 = 0.997) was close to unity. Adsorption thermodynamics study represented that EBT adsorption onto the DF-120 commercial AEM was an exothermic process (ΔH°= −79.78 KJ/mol). In addition, the regeneration of DF-120 commercial AEM was also studied.

Propane-1,3-bis(hexadecyldimethylammonium bromide)-bentonite-based novel hybrid material for the elimination of textile dyes

This work addresses intercalation of a gemini surfactant, propane-1,3-bis(hexadecyldimethylammonium bromide) (g-16–3-16), into bentonite (Bt) clay for developing a novel hybrid material which can eliminate dyes from the wastewater. The prepared g-16–3-16-Bt hybrid material was characterized through FTIR, XRD, SEM-EDX, and BET. The material exhibited an approximate removal efficiency of 95 % for congo red (CR) and eriochrome black T (EBT) under optimal conditions (pH = 3, concentration of dyes = 10 mg/L, adsorbent dose = 2 g/L, equilibrium time = 180 min., temperature = 25 °C). With increase in concentration of both the dyes (1 to 25 mg/L), the g-16–3-16-Bt demonstrates a notable increase in adsorption capacity towards CR (0.4 to 11.1 mg/g) and EBT (0.5 to 10.7 mg/g), respectively. The adsorption was examined with several co-existing ions and found that among the Mg2+, Ca2+, Ni2+, Cu2+, EDTA, sulphate, bicarbonate and glycine, only bicarbonate and Mg2+ slightly impacted the EBT removal (from 95 % to 83 % and 78 %, respectively), whereas all affected in the case of CR. With a rise in the NaCl concentration, the efficiency of g-16–3-16-Bt towards CR removal declined (from 88 % to 62 %) considerably, however, it did not affect much with EBT. The results of adsorption studies were found to follow pseudo-second-order kinetic model and match well with the Langmuir isotherm. The maximum adsorption capacity of g-16–3-16-Bt towards CR and EBT were found to be 30.95 and 19.15 mg/g respectively. The g-16–3-16-Bt hybrid material exhibited a good efficiency even after 4th adsorption–desorption cycle (∼79 % removal) and was found to be efficient for the elimination of CR and EBT from real wastewater.

Functionalised mesoporous biosorbents for efficient removal of hazardous pollutants from water environment

Wastewater from industrial complexes contains a significant amount of non-biodegradable azo dyes that present a hazard to animals, plant life and humans. The sorbents from biomass are showing a promising potential for the removal of azo dyes through biosorption. Hence, this research presents the capability of using pomegranate peel (Punica granatum) as a novel biosorbent for the uptake of azo dye Eriochrome Black T (EBT) from an aqueous solution. The effective removal of EBT was monitored by adjusting sorption parameters including pH value, mass of the biosorbent, EBT concentration and consecutively studying the sorption kinetics. The samples of biomass were analysed by various instrumental techniques and physio-chemical methods. After sorption experiments concentration of Eriochrome Black T was analysed by UV–Vis spectrophotometer. The removal of EBT was found to be optimal at the pH value of 3 with 100 mg of biosorbent by EBT concentration of 150 mg/L during a contact time of 90 min at room temperature. Under these conditions, the adsorption capacity was determined as 46.10 mg/g. By examining the adsorption kinetics, it was found that biosorption takes place through a combination of different mechanisms from which the pseudo-second-order model (r2 = 0.99), takes up the major role. The values of the correlation coefficients for the investigated models of isotherms show the best agreement with Langmuir's (r2 = 0.97) and Temkin's (r2 = 0.92) models. The novel data of cost evaluation classifies pomegranate peel as a low-cost adsorbent with promising potential for the removal of investigated azo dye, while the adsorption process is economically feasible (0.034$ for the uptake of 1 g dye molecule) paving the way for new biotechnological advances in wastewater decontamination.

Carbon-Tunable p-type ZnO Nanoparticles for Enhanced Photocatalytic Removal of Eriochrome Black T

Zinc oxide-mediated photocatalysis is a promising alternative to TiO2 photocatalysis, especially for the purpose of removal of recalcitrant organic dye pollutants. Highly crystalline, nanoscopic carbon-doped ZnO was successfully synthesized via combined precipitation and mechanochemical approach and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and Fourier transform infrared (FTIR) spectrometry. The obtained photocatalysts depict plate-like morphology and hexagonal wurtzite structure. The XRD, SEM, and FTIR analyses were in good agreement with EDX results. The 5wt % C-doped ZnO showed remarkable visible light-photocatalytic activity based on the degradation of Eriochrome Black T (EBT), and exhibits the best point of zero charge (pHpzc) for a favorable adsorption equilibrium. This degradation process was optimized at 97 % using response surface methodology (RSM) using a 0.1 g C-ZnO, 5.00 mg/L EBT and pH 11. The associated kinetic data fit the pseudo-first-order kinetic model. The resulting C-ZnO was a p-type with a good pH at zero-point charge that permits the substantial removal of EBT by C-doped under visible light irradiation over a wide range of initial pH.

Kinetic, Thermodynamic and Adsorption Isotherm Studies of Detoxification of Eriochrome Black T Dye from Wastewater by Native and Washed Garlic Peel

Eriochrome Black T (EBT) is mutagenic and carcinogenic, and thus its presence in water may result in severe illnesses. This study was aimed at adsorbing EBT from simulated water samples by using a batch adsorption process, onto native (GP) and washed garlic peel (WGP). Surface and structural characterization of native and washed GP was performed using FTIR, SEM, BET, and BJH analysis. The effects of several parameters, affecting the process of adsorption, like pH, temperature, contact time, adsorbent dose, and initial dye concentration, were also examined. Freundlich and Langmuir isotherms were applied to the equilibrium data. Pseudo-first and pseudo-second order models were used to study the adsorption kinetics. The Langmuir isotherm and pseudo-second order model perfectly explained the equilibrium data. ΔG°, ΔH°, ΔS° studies indicated that adsorption of EBT onto GP and WGP was a favorable, spontaneous, and physical process. Maximum dye removal by GP (96%) and WGP (82%) was observed at pH 2. Similarly Maximum adsorption capacities were found to be 99.5 mg/g and 89.4 mg/g for GP and WGP, respectively. It is concluded from these results that garlic peel can be used as a cheaper and more efficient material for the adsorptive removal of EBT from contaminated water samples.

Statistical physics modeling and evaluation of adsorption properties of chitosan-zinc oxide nanocomposites for the removal of an anionic dye

The development of rapid methods to synthesize cost-effective adsorbents for the dye removal is an emerging and relevant topic in the field of wastewater purification. This study focuses on the preparation of zinc-oxide nanoparticles (NPs) impregnated chitosan (CS@ZnO) nanocomposite beads via mechanical stirring (MS) and microwave-assisted (MA) routes. The beads were characterized and utilized for the removal of Eriochrome Black-T (EBT) dye. Results showed that the CS@ZnO-MA beads provided the best adsorption capacities for EBT removal (40.9 ± 0.83 mg g−1) at pH 3.5. The best composite (CS@ZnO-MA) can be regenerated 5 times without significantly affecting its adsorption properties and can remove 71 % of EBT dye from a multi-pollutant solution. The novelty of this study relies on the facile preparation and impregnation of the biopolymer with metal-oxide NPs, which render high adsorption capacity, mechanical strength and high specific surface area of the CS to contribute in the removal of dye molecules from textile wastewater. An enhanced statistical physics model revealed that the adsorption mechanism of EBT dye molecules on these composites was multimolecular. The study indicates an effective synthesis route that can be implemented to prepare new adsorbents using CS at a large-scale for water treatment.

Biosorption of Eriochrome Black T Using Exserohilum rostratum NMS1.5 Mycelia Biomass

The presence of eriochrome black T (EBT) dye in waste water causes a significant hazard to human health and ecology. In the current study, biosorption was employed to eliminate EBT from water. Thus, we utilized endophytic fungi strain Exserohilum rostratum NMS1.5 mycelia biomass as biosorbent agent. The process was carried out at room temperature by magnetic stirring. The results indicated that an increase in pH would decrease adsorption capacity and removal percentage. In addition, an increased EBT concentration would decrease the removal percentage and increase biosorption capacity. The equilibrium time indicated that after 300 min of mixing, the percentage removal and biosorption capacity were 80.5% and 100.61 mg/g, respectively. The biosorption isotherms and kinetics were compatible with the Freundlich model and the pseudo-second-order. This research indicates that E. rostratum NMS1.5 may be utilized as an environmentally friendly and affordable alternative biosorbent material for EBT removal.

Efficient Removal of Eriochrome Black T Dye Using Activated Carbon of Waste Hemp (Cannabis sativa L.) Grown in Northern Morocco Enhanced by New Mathematical Models

In the present work, the adsorption behavior of Eriochrome Black T (EBT) on waste hemp activated carbon (WHAC) was examined. The surface of the WHAC was modified by H3PO4 acid treatment. The surface and structural characterization of the adsorbents was carried out using Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis. The effect of influential adsorption parameters (pH, contact time, dosage, and initial concentration) on the adsorption of EBT onto WHAC was examined in batch experiments; some adsorption parameters such as pH, concentration and dose were improved by new mathematical models. The adsorption behavior of EBT on the surfaces of WHAC was evaluated by applying different isotherm models (Langmuir, Freundlich, Temkin and Dubinin–Radushkevich) to equilibrium data. The adsorption kinetics was studied by using pseudo-first-order, pseudo-second-order, Elovich and intraparticle models on the model. Adsorption followed the pseudo-second-order rate kinetics. The maximum removal of EBT was found to be 44–62.08% by WHAC at pH = 7, adsorbent dose of 10–70 mg, contact time of 3 h and initial dye concentration of 10 mg.L−1. The maximum adsorption capacities were 14.025 mg.g−1 obtained by calculating according to the Langmuir model, while the maximum removal efficiency was obtained at 70 mg equal to 62.08% for the WHAC. The adsorption process is physical in the monolayer and multilayer.

Engineered biochar supported layered double hydroxide-cellulose nanocrystals composite-: Synthesis, characterization and azo dye removal performance

In this work, engineered biochar decorated layered double hydroxides and cellulose nanocrystals (B–CuFe–CNC) biocomposites were synthesized by the facile ultrasonicated-co-precipitation technique. The biocomposite was investigated for purification of Eriochrome Black T (EBT) dye from water. The characterization results showed that the presence of CNC in biochar-layered double hydroxides resulted in a two-dimensional rod-like structure with excellent crystallinity, improved surface functionalities, and provides an attractive platform for the enhanced adsorption of azo anionic dye molecules. The adsorption system was appropriately demonstrated by the BBD-RSM (R2 > 0.994). The biocomposite exhibited higher EBT adsorption in the acidic pH range (2–5) due to strong electrostatic and chemical interactions. The kinetic and isotherm results were well demonstrated by pseudo-second order, Freundlich, and Redlich Peterson models. The maximum adsorption capacity of biocomposite was 876.2 mg/g achieved within 45 min. The spectroscopic analyses imply that the high removal of EBT by biocomposite is mainly governed by electrostatic attraction, hydrogen bonding, and chemical/metal complexation mechanisms. The biocomposite maintained high EBT removal after six successive adsorption cycles and excellent dye adsorption in the different water matrices. The results suggest that tailoring biochar properties with layered double hydroxide and CNC is a promising way for the enhanced removal of dye contaminants from wastewater.

Enhanced removal of Eriochrome Black T from water using biochar/layered double hydroxide/chitosan hybrid composite: Performance evaluation and optimization using BBD-RSM approach

In this research work, a novel hybrid composite consisting of biochar (B), layered double hydroxide (CuFe) and chitosan (CS) (B-CuFe-CS) was produced using an ultrasonication-assisted co-precipitation method. The resultant composite was employed for adsorptive removal of Eriochrome black T (EBT) from water. Physicochemical characterization indicated that the B-CuFe-CS containing 10 wt % CS exhibited a heterogeneous structure with better crystallographic and textural characteristics. The B-CuFe-CS with abundant surface functionalities (-CO, -C-O, –OH, –NO3, and MMO), facilitates faster and enhanced removal of the EBT. The kinetic results showed better fitting to the pseudo-second order model, and equilibrium was achieved within 30 min. Equilibrium data was well explained by Langmuir and Redlich Peterson isotherm models (R2 > 0.98), indicating the EBT removal onto B-CuFe-CS followed monolayer adsorption. The maximum adsorption capacity was 806.4 mg/g, which was higher than pristine B–CuFe (476.19 mg/g) and many other adsorbents. The spectroscopic analysis (FTIR and XPS) and experimental results suggested that EBT adsorption is mainly governed by electrostatic, chemical and anion-exchange interactions. It is evident from these results that coupling B–CuFe composite with bio-filler (chitosan) resulted in an efficient bio-adsorbent to effectively purify dye-contaminated water streams.

On the use of metal-organic framework-based adsorbent from recycled PET bottles for Eriochrome Black T removal

In this study, a metal–organic framework (MOF) adsorbent from recycled polyethylene terephthalate (PET) bottles was developed to effectively remove Eriochrome Black T (EBT) dye present in synthetic wastewater. A sustainable, “greener” route of MOF synthesis was adopted involving microwave-enabled depolymerization of PET to terephthalic acid (TPA) and conversion of the latter to its organic salt linker form. Results from differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA) not only revealed the structure of the as-prepared MOF, but also proved the presence of EBT molecules on the adsorbent during the dye removal process. A ∼77% maximum removal was reached after 90 min and the adsorption was best explained by Langmuir model having 82.5 mg/g maximum monolayer capacity. Kinetic studies also showed the adsorption to be pseudo-second order with a two-stage intraparticle diffusion process. The effective performance of MOF on EBT removal was also verified by the presence of potential adsorbent-adsorbate interactions such as ionic, hydrogen bonding, and π–π stacking. Thus, the as-fabricated PET-derived MOF is considered a decent, value–added material acting as a sustainable adsorbent for organic dyes present in contaminated water.

Azo Dye Adsorption onto Cobalt Oxide: Isotherm, Kinetics, and Error Analysis Studies

The current study focused on utilizing cobalt oxide to eliminate hazardous Eriochrome Black T (EBT) dye. The impact of pH (2, 4, 7, 8, and 10) and temperature (45, 50, and 55 °C) was examined for EBT removal. The results show that the maximum sorption occurred at pH = 2 and that the removal percentage increased with increasing temperature. Five non-linear regression methods were used to predict the best isotherm and kinetic models. A coefficient of non-determination, K2, was very helpful for selecting the RMSD function as a preferable error function among the five methods. Isothermal models to illustrate equilibrium sorption information, the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models were used. The results showed that the Langmuir model (R2 = 0.99) was the most favorable, indicating monolayer sorption of EBT occurred. The kinetics models were analyzed using pseudo-first-order and pseudo-second-order whereas the sorption information was well described by the pseudo-second-order model (R2 = 0.99). The results of the thermodynamic study appeared that the adsorption of EBT was endothermic, feasible, spontaneous, and physical adsorption.

Adsorption and reusability performance of M-Fe (M = Co, Cu, Zn and Ni) layered double hydroxides for the removal of hazardous Eriochrome Black T dye from different water streams

In this study, layered double hydroxides (LDHs) containing M (Co, Cu, Zn and Ni) and Fe were produced and employed for the removal of Eriochrome Black T (EBT) dye from different water matrices. The characterization results showed that the CuFe and CoFe LDH exhibited excellent crystallinity and excess surface hydroxyl groups with better textural properties compared to ZnFe and NiFe LDH. Adsorption of EBT onto M-Fe LDH was found higher in the acidic pH range (2−4). The EBT adsorption process onto M-Fe LDH followed the pseudo-second order kinetic model, and isotherm was better described by the Redlich-Peterson (R-P) model. The maximum adsorption capacity of CoFe, CuFe, ZnFe and NiFe LDH was 136.98, 250, 123.45, 123.43 mg/g, respectively at initial dye concentration of 200 mg/L, pH 2.5, contact time 120 min and temperature 298 K. The mean free energy calculated from D–R model was >40 kJ/mol for CoFe and CuFe LDH and <40 kJ/mol for ZnFe and NiFe LDH, implying that the removal of EBT was achieved by chemisorption and physisorption, respectively. The adsorption performance of prepared LDHs after three successive regeneration cycles followed the order: CuFe> CoFe > NiFe > ZnFe. Interestingly, compared to other LDHs, CuFe LDH exhibited better physicochemical properties and showed higher adsorption and reusability performance for the removal of EBT dye in the different water matrices. This indicated that the CuFe LDH could be applied as an effective adsorbent for decontamination of anionic dyes in industrial effluents.

Biochar supported CuFe layered double hydroxide composite as a sustainable adsorbent for efficient removal of anionic azo dye from water

This study reports the synthesis of date palm waste-derived biochar (B) supported CuFe layered double hydroxides (CuFe LDH) composite by facile co-precipitation method. The adsorption performance of B-CuFe composite was evaluated for the removal of Eriochrome black T (EBT), as a model anionic azo dye, from the aqueous phase. The B-CuFe composites were characterized by FTIR, XRD, TGA, SEM-EDX and BET techniques. Characterization results revealed the synergistic effect of biochar and CuFe LDH has resulted in substantial improvement in physicochemical characteristics (i.e. surface functionality, surface area and surface morphology) of B-CuFe composite, which promotes rapid and improved adsorption of (EBT) from the solution. The B-CuFe composite with 2.5 g loading of biochar onto CuFe LDH - showed better adsorption performance than that of other B-CuFe composites. The adsorption process of EBT onto B-CuFe composite was well described by the RSM models (with R 2 = 0 . 964 – 0 . 999 ). Acidic pH (2–5) and higher temperature favored the adsorption of EBT onto B-CuFe composite, and almost (70–85%) of EBT was removed from the water within the first 15 min. The highest adsorption capacity, 565.32 mg/g of EBT onto B-CuFe composite, was obtained at pH 2.5 and 45 °C. The adsorption mechanism associated with the strong electrostatic and chemical interactions of EBT sulfonated anions (SO 3 − ) with protonated hydroxyl surface groups ( OH 2 + ) of B-CuFe composite. The B-CuFe composite exhibited better EBT removal in the presence of co-existing anions and demonstrated excellent reusability performance (11% reduction) after five successive cycles. The results demonstrated that the B-CuFe composite has a great potential to be employed as a sustainable and cost-effective adsorbent for the purification of dye contaminated water bodies. • Sustainable biochar-CuFe composite was fabricated by the coprecipitation method. • B-CuFe exhibited improved physicochemical properties than pure biochar and CuFe. • B-CuFe removed 85% of Eriochrome black T dye from the water in 15 min. • The maximum adsorption capacity of B-CuFe was 565.32 mg/g at 45 °C. • B-CuFe composite exhibited excellent reusability performance.

Adsorptive removal of eriochrome black T (EBT) dye by using surface active low cost zinc oxide nanoparticles: A comparative overview

The ecological toxicity imparted by non-biodegradable organic dyes has been considered as a major risk to handle in front of mankind. In this view, the low-cost zinc oxide nanoparticles (ZnO-NPs) were facially synthesized by coating the surface with surfactant (CTAB) and ionic liquid (BMTF) molecules for the effective removal of Eriochrome Black T (EBT) from aqueous media. Various advanced characterization techniques have given insight into the morphological features, crystalline structure and physio-chemical properties of as-synthesized ZnO-NPs. The systematic analysis of the adsorption isotherms and kinetics models specifies that the adsorption of EBT follow Freundlich model and pseudo-second-order kinetics. The intraparticle diffusion model displayed a linear relationship (R2 = 0.98, 0.97 and 0.94 for BMTF@ZnO, CTAB@ZnO and bare ZnO-NPs), which shows that pore diffusion rate is affected by surface modification and effects the overall EBT adsorption process. Furthermore, after the removal of 87% and 84% of EBT dye by BMTF@ZnO-NPs and CTAB@ZnO-NPs, the fabricated nanoadsorbents of ZnO were successfully regenerated and reused after the treatments up to four times. The adsorption aptitude of ZnO-NPs towards EBT dye was systematically explored in real wastewater samples and interference study of inorganic metallic salts was also performed. The toxicity estimations of the treated dye solutions were made using floral and fungal activities, to ascertain their non-toxic nature before releasing into the environment. These outcomes have supported the immense potential of ZnO-NPs towards the removal of EBT in a cost effective manner.

Adsorption of Eriochrome black-T from aqueous environment by raw Montmorillonite

ABSTRACT The present study aimed to investigate the removal of the azo dye, Eriochrome black-T (EBT) from the synthesised effluents using the Montmorillonite (MM) raw clay. MM is a soft phyllosilicate group of minerals and has been used as a low-cost adsorbent for the removal of pollutants from the environment. In this regard, the effect of several factors, such as contact time, pH, adsorbent dose, initial dye concentration, solution ion strength, and temperature in the batch system was assessed. Fourier transformed infrared (FTIR) spectroscopy and X-ray diffractometer (XRD) techniques were also employed to examine the MM. Adsorption capacity of EBT in equilibrium time equal to 20 min was attained 57.88 mg/g. Removal of EBT by the MM illustrated that the data had a good fit with the models of pseudo-second-order and Freundlich isotherm. The contact time and pH were also optimised at 20 min and pH = 3, respectively. The maximum adsorption capacity (72.71 mg/g) was obtained for pH value of 3. Based on the value of RL in this study (RL = 0.70), the adsorption process of EBT removal using MM was favourable. The results from this study confirmed the effectiveness of MM as an inexpensive and eco-friendly option for the adsorption and removal of EBT from polluted water.

Modified wheat straw-derived graphene for the removal of Eriochrome Black T: characterization, isotherm, and kinetic studies.

A cost-effective and environment-benign adsorbent was prepared from an abundant agro-waste material. Wheat straw was reduced to graphene and then modified by crosslinking to epichlorohydrin. During the conversion process of wheat straw to graphene, the specific surface area increased more than 100 times (from 4 to 415 m2 g-1). The adsorption efficiency of raw wheat straw, graphene nanosheets, and modified graphene against Eriochrome Black T (EBT) were 8.0, 34.7, and 74.4%, respectively. The modified graphene was further investigated for the effect of environmental condition, i.e., pH (3 to 11), EBT concentration (25-100 mg L-1), adsorbent dosage (0.25-0.75 g L-1), contact time (5-60 min), and solution temperature (30-60 °C). The dye removal remained at a high level under a wide range of pH from 3 to 9. The EBT removal decreased from 87.3 to 54.5 by increasing dye concentration and increased from 38.2 to 85.4% by increasing adsorbent dose in the studied ranges. Dye removal also increased by mixing time from 5 to 30 min, whereas a slight drop was observed by continuing agitation up to 60 min. Conducting experiments at various temperatures revealed an endothermic process. Pseudo-first-order and pseudo-second-order models were adequate to represent the adsorption kinetics. Isotherm models suggest a multilayer adsorption of EBT molecules on heterogeneous modified graphene surface with a maximum adsorption capacity of 146.2 mg g-1. The present work demonstrated that the modified graphene obtained from available and low-cost agro-wastes could be used effectively as adsorbent against EBT from aqueous media.