Maximum Dye Removal Efficiency Research Articles

Tailored nano clay blends for enhanced dye mixture adsorption in wastewater treatment

Natural clays are eco-friendly, cost-effective, and industrially acceptable adsorbents employed in wastewater treatment. Textile effluents contains mixture of dyes where a single adsorbent often fails to treat completely. Herein, the simplest strategy for the efficient treatment of effluent with multicomponent pollutants using an tailored blend of two clay minerals has been presented. This strategy was studied using a binary blend of halloysite and montmorillonite clays (HAMT) to remove a mixture of industrial dyes, reactive Black-B (BB) and methyl red (MR) from the model effluent. Here, halloysite (HA) and montmorillonite (MT) selectively adorbs reactive black-B and methyl red respectively and could not completely treat model effluent individually whereas HAMT blend proved to be most effective. HAMT blend was prepared by convenient ultra-sonication assisted solution process and characterized using the various analytical techniques such as FT-IR, DR-UV spectra, XRD and SEM to determine structural, morphological features. Adsorption of model effluent studied as a function of pH, time, adsorbent loading and adsorbate concentration. The dye removal efficiency was remarkably enhanced when the HAMT blend was used according to the concentration of dyes present in the model effluent. The maximum dye removal efficiency was attained using HAMT (1:1) blend for effluent with an equimolar concentration of selected dyes. Similarly, HAMT (2:1) found suitable for the treatment of real textile effluent collected from local textile industries based on its assessment. This study aids in the development of a tailored adsorbent blend using conventional adsorbents for complex effluent treatment in a cost-effective way, eliminating the need for specialized materials.

Innovative cellulose-lactone hybrid material for efficient rhodamine 6G dye adsorption: Synthesis and characterization

This study uses a simple solvent casting technique to offer an innovative, cost-effective synthesis of a cellulose-lactone hybrid material for Rhodamine 6G dye adsorption. The modified cellulose revealed superior adsorption competencies, triumphing a maximum dye removal efficiency of 97.8 % under neutral pH. Adsorption isotherms were best defined by the Langmuir model (R2 = 0.999), signifying monolayer adsorption, while the Freundlich model (R2 = 0.9714) suggested the existence of heterogeneous adsorption sites. Characterization methods, including FTIR, TGA, DSC, and SEM, confirmed the structural, thermal, and morphological changes induced by lactone modification, which enhanced the material's mechanical properties and adsorption efficiency. The hybrid material demonstrated excellent long-term stability, recyclability, and potential for large-scale water treatment applications. These findings emphasize the material's potential as a sustainable solution for removing organic pollutants from wastewater.

Preparation and Characterization of Acid and Base Modified Fish Scales of Labeo Rohita and Their Application as an Adsorbent

The study is carried out to investigate the removal efficiency of the textile dye Congo Red (CR) on fish scales (FS) of Labeo rohita. Huge fish scales are dumped as waste from the fish markets and are not converted into valuable products. That is why a fish scale of widespread fish in Bangladesh Labeo rohita has been selected as an adsorbent in removing Congo red from an aqueous solution. In the present study, the effect of different parameters such as adsorption dosage, contact time, concentration of dye, and pH on the removal of CR were investigated. The maximum dye removal efficiency (88.53 %) was observed for 3g/100 mL of adsorbent at an initial concentration of 1×10-4 M and pH 8.80 after 60 minutes. Modification of the surface of the fish scales was carried out by using HCl and KOH. The surface of the adsorbents was characterized by FTIR spectroscopy. After 60 minutes of contact time, the percentage of adsorption for the acid and base-modified FS was 54.81% and 90.51% respectively. The higher intense FTIR spectra of the base-modified FS denoted the better efficiency of the adsorbent at the basic medium. The adsorption kinetics of CR on FS is studied by following the pseudo-first-order and pseudo-second-order kinetic model. Experimental results showed that fish scales of Labeo rohita have satisfying color removal efficiency and might be a better alternative to other adsorbents to detoxify industrial wastewater. A mechanism of adsorption of CR on FS has been proposed.

Effect of solvothermal reaction time on adsorption and photocatalytic activity of spinel ZnFe2O4 nanoparticles

The present investigation explored the impact of solvothermal reaction time on the adsorption properties of synthesized spinel ZnFe2O4 Nanoparticles (ZF NPs) and their photocatalytic activity for the degradation of congo red (CR) dye. The structure, morphology and chemical composition is identified for the synthesized ZF NPs. The reaction times for the solvothermal synthesis of ZF NPs were investigated at time intervals of 6 hrs and 18 hrs which are denoted as ZF-6 h and ZF-18 h respectively. The XRD confirms the formation of spinel-type ZF-6 h and ZF-18 h with crystallite size of 5.50 nm and 8.36 nm for ZF-6 h and ZF-18 h respectively. The FESEM image of ZF-6 h exhibits microspheres, whereas in ZF-18 h NPs, the microspheres undergoes deformation. TEM analysis of ZF-6 h revealed that the microspheres were consists of 8–10 nm size ZF-NPs. Raman spectroscopy and XPS studies indicates, the reaction time influence the occupancy with 64 % and 32 % of inversion of Zn2+ cations from tetrahedral to octahedral sites in ZF-6 h and ZF-18 h, respectively. The surface area of mesoporous ZF-6 h and ZF-18 h are 138.29 m2/g and 128.41 m2/g respectively as confirmed using BET and BJH techniques. The CR dye adsorption capacity of 123.73 mg/g for ZF-6 h is higher compared to ZF-18 h (99.93 mg/g). The maximum dye removal efficiency evaluated for ZF-6 h NPs and ZF-18 h NPs was 87.33 % and 73.09 % respectively upon exposure of natural sunlight. The recyclability study identifies that ZF-6 h NPs remain stable for three degradation cycles. These results indicate that reaction time in solvothermal synthesis is sensitive to the morphology and physicochemical properties of ZF NPs. The enhanced performance of such ZF NPs is attributed to the synergistic effect of adsorption followed by photocatalytic (photo-Fenton) degradation of dyes.

UIO-66 (Zr)-Metal Organic Frameworks for oil orange SS adsorption from aqueous effluent towards eco-friendly wastewater management

Abstract Wastewater treatment is essential for efficient removal of harmful substances such as dyes and organic contaminants from aqueous streams. In this regard, metal-organic frameworks (MOFs) are introduced by academia owing to their superior properties that including efficient adsorbents as well as reliable semi-permeability. Thus, such characteristics are making them attractive for wastewater treatment applications. The experimental results revealed that the modified MOF structures namely, UIO-66 (Zr) possess a superior adsorption capacity for orange SS dye. The influence of pH value, the temperature, adsorption isotherm time, initial pollutant load, as well as coexisting ions is highlighted. Initially, 30-minutes of reaction contact time is monitored as the isotherm time. The experimental results demonstrate a maximum dye removal efficiency of 100% and an adsorption capacity of 2062.175 mg/g is investigated. Such outcomes confirm the efficient adsorption capacity of UIO-66 (Zr) based MOF material for dye elimination.

Cellulose Acetate Supported MOF-5/Crystalline Nanocellulose Composite Film as an Adsorbent Material for Methylene Blue Removal from Aqueous Solutions.

In this study, a novel, low-cost, and efficient adsorbent film was fabricated by a solvothermal method. The adsorbent film was developed to be hydrolytically stable, not vulnerable to aggregation in aqueous environments, and not prone to secondary contamination. The adsorbent consists of cellulose acetate (CA) as a support embedded with a MOF-5/crystalline nanocellulose (CNC) composite material. The CA-supported MOF-5/CNC film was characterized using a variety of techniques, including X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy, which revealed hydroxyl and carbonyl functional groups on the adsorbent film. The film was evaluated for the adsorptive removal of methylene blue (MB) from an aqueous solution. Adsorption was characterized by a rapid increase in MB adsorption during the first hour with equilibrium achieved within 4-5 h into the adsorption process. The maximum adsorption capacity was determined to be 4.29 mg/g and the maximum dye removal efficiency was 77%. The MB adsorption process best fitted the Freundlich isotherm and pseudo-second-order kinetic models. Thermodynamic studies showed that the adsorption was exothermic and feasible. The adsorbent film showed admirable regeneration ability, demonstrating its cost-effectiveness and its potential as a promising material for wastewater treatment.

Removal of Rhodamine-B dye from Aqueous Solutions Using Alkaline-Modified Activated Carbon from Cocoa Pod Husk.

Rhodamine-B (RhB) dye in wastewater poses health and environmental risks due to respiratory and eye infections, neurotoxicity, and carcinogenicity, necessitating proper disposal for risk mitigation. This study investigates RhB removal from water using NaOH-modified activated carbon derived from cocoa pod husk (CPHAC). Employing a face-centered central composite design, operational variables were optimized to achieve maximum RhB dye removal efficiency. The study reveals a removal efficiency of 98.87 ± 0.84% under optimized conditions: adsorbent dose of 1.34g, contact time of 71.59min, and an initial RhB concentration of 6.61 ppm. The Freundlich isotherm model demonstrated a good fit, suggesting that RhB removal is governed by heterogeneity and multilayer adsorption. Kinetic experiments revealed that adsorption follows a pseudo-second-order model, indicating likely irreversible adsorption with dye molecules forming chemical bonds on CPHAC's surface. Overall, this study demonstrates the effectiveness of CPHAC as an efficient adsorbent for RhB removal from water.

Kinetics studies and effect of the process parameters on the biodegradation of methyl orange dye

The biodegradation of methyl orange dye using Stenotrophomonas maltophilia (HE963840.1) bacteria was studied. The optimization of the biodegradation process has been performed using central composite design (CCD) of response surface methodology (RSM) with respect to three parameters namely temperature, initial dye concentration and inoculum dose. The response is best described by the second order polynomial with R2 value of 0.99. The optimized values of the process parameters were empirically checked and the model equation of the RSM was found statistically significant. The errors between experimental and model predicted results were found to be less than 8 %. The maximum dye removal efficiency was found as 86.5 ± 0.1 %. The growth kinetics of the bacteria was also studied and it is best described by Andrew-Haldane model. The values of kinetic parameters maximum specific growth rate (μmax), inhibition constant (KI) and saturation constant (KS) were found as 0.032 h−1, 156 mg/L and 78 mg/L respectively.

Synthesis of iron loaded jackfruit peel biochar through microwave heating as a stable and active heterogenous Fenton catalyst for dye degradation

Iron-loaded biochar derived from jackfruit peels (Fe-JP) was synthesised by pyrolysis in a microwave furnace and iron was loaded onto the peels prior to pyrolysis, facilitated by sonication. The primary objective of the investigation was to examine the degradation process of methylene blue (MB) dye and Acid Red 1 (AR1) dye by the using Fe-JP biochar as a heterogeneous Fenton catalyst. The investigation encompassed an examination of the impact of different operating parameters, such as pH, catalyst dosage, and H2O2 concentration. The synthesised Fenton catalyst underwent characterization using Field Emission scanning electron microscopy (FESEM), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques, Fourier transform infrared (FTIR) spectra analysis, Raman spectroscopy, Brunauer-Emmet-Teller (BET) analysis. At a pH of 3, using an initial MB dye concentration of 20 mg/L and initial AR1 dye concentration of 50 mg/L, an 8 mM H2O2 concentration, and a catalyst dose of 2 g/L, the maximum dye removal efficiency reached 96.5 % and 98 % respectively, while the total organic carbon (TOC) removal efficiency reached 68.5 % and 75 % respectively. The observed reaction time under the given experimental conditions was 120 min. The thermal stability of the biochar catalyst was found to be excellent based on the Thermogravimetric analysis (TGA) and Differential Scanning Calorimeter (DSC) studies. The catalysts that were developed demonstrated remarkable durability and negligible leaching of iron, hence enabling their repeated usage in subsequent cycles. The findings of the investigation suggest that the primary mechanism responsible for the degradation of the dye was the surface-based heterogeneous Fenton activity. Additionally, the effect of adsorption on the elimination of colour under varying pH conditions was examined, which had a very low influence in dye degradation (<30 %). The conducted scavenging investigations in the research have indicated the major involvement of hydroxyl radicals (OH) in the degradation process, followed by surface-bound hydroxyl radicals (OHsurface), superoxide radicals (O2−) and ultimately by singlet oxygen radicals (1O2). The study's economic analysis demonstrated that using microwave mode of heating for catalyst synthesis is both green and cost-effective. This observation suggests the possibility of practical implications in the domain of dye degradation.

Assessment of Natural Bentonite Efficacy for Dye Removal in Textile Wastewater Treatment : Implication for Mitigating River Citarum Pollution

Textile industries contribute significantly to the economy but release harmful pollutants into the environment, especially rivers. The effluent from the textile industry contained toxic dyes that can harm the river ecosystem. Several studies have been conducted to reduce toxic dyes in a river system using bentonite as an adsorbent to reduce river pollution effectively. However, the effectiveness of bentonite still needs to be tested again using textile liquid waste that has not gone through any waste processing at all. Citarum is one of the main rivers on Java Island, which suffers from textile effluent, especially azo dyes which are toxic, mutagenic and carcinogenic which can harm the aquatic ecosystem. Therefore, this study aims to implement natural bentonite as an adsorbent to remove dyes from textile wastewater. We performed a laboratory test to adsorption on bentonite and textile wastewater considering the variation of adsorbent weight of 10 g and 20 g in 100 mL of textile wastewater stirred in an Erlenmeyer flask at room temperature for 0-300 minutes. The initial concentration of textile wastewater used was 10%, 30%, and 50%. We found that the maximum dye removal efficiency was 91.25% with 10% initial concentration treatment, 20 g adsorbent weight, and 60 minutes contact time. Longer contact time will increase the removal efficiency and adsorption capacity, while higher adsorbent dosage will decrease the concentration of dyes in wastewater. Efficient textile wastewater treatment has improved water quality, effectively meeting river water quality standards and environmental regulations.

Investigation of the efficacy of Alhagi maurorum plant powder for Janus Green B dye removal from wastewater

The growth of industrial activities, has led to a significant increase in the influx of color pollutants into the environment. Phytoremediation can play a crucial role in enhancing wastewater quality. Accordingly, this study sought to evaluate the effectiveness of Alhagi maurorum plant powder in removing Janus Green B (JGB) dye from aqueous solutions. The adsorbent’s properties were characterized through Fourier-transform infrared spectroscopy. The study examined various parameters, including initial dye concentration (20–110 mg/L), adsorbent dosage (0.002–0.02 g), solution pH (2–10), and contact time (5–50 min). The experiments revealed that the maximum dye removal efficiency, 99.51%, was achieved under optimal conditions: pH 7, a contact time of 20 min, an adsorbent dosage of 0.01 g, and an initial dye concentration of 90 mg/L. The adsorption of JGB onto the adsorbent followed the Langmuir isotherm model, with a maximum adsorption capacity of 90.909 mg/g. The kinetic results supported a pseudo-second-order model for the adsorption process, with an R 2 value of 0.9999. The calculated Gibbs free energy changes (ΔG°) at temperatures of 288, 298, 308, 318, and 328 K were found to be −5354.28, −5993.61, −6439.66, −7026.51, and −7932.05 kJ/mol, respectively, indicating the spontaneity of the adsorption process.

Utilization of Eco‐friendly Copper Oxide Nanoparticles and Iron Oxide Nanorods in Dye Removal from Real Textile Industry Effluent

AbstractTextile industry wastewater contaminated with dye effluents poses a significant environmental challenge. Numerous nanoparticles are used as adsorbents to treat similarly stimulated wastewater, but particularly nanomaterials synthesized through green methods have gained prominence. To assess their practical applicability in addressing real‐world textile wastewater pollution, studies on dye removal from authentic textile industrial effluents are recommended. As a result, a study focused on the removal of dye from real textile industrial effluent is conducted, and biosynthesized copper oxide nanoparticles and iron oxide nanorods are chosen as adsorbents. The investigation scrutinized the influence of adsorbent dosage, adsorbent‐adsorbate contact time, and wastewater pH on the percentage of dye adsorption. These findings indicate that increasing the adsorbent dosage and contact time leads to a higher percentage of dye removal. Notably, copper oxide nanoparticles exhibit superior dye removal efficiency at pH levels 5 and 7, outperforming the maximum dye removal efficiency of iron oxide nanorods at pH 12. The study achieved an impressive process efficiency of 95.24% for copper oxide nanoparticles and 62.5% for iron oxide nanorods. Response surface methodology (RSM) is employed for statistical data analysis and optimization of dye removal process parameters to maximize efficiency. Overall, the results demonstrate that biosynthesized nanomaterials offer a promising and effective solution for removing dyes from textile industrial wastewater.

Removal of anionic azo dye from wastewater using Fe3O4 magnetic nanoparticles adsorbents in a batch system

This work investigates removing the anionic azo dye from wastewater using Fe3O4 magnetic nanoparticle adsorbents in a batch system. The effects of adsorbent dosage (0.1–0.5 g/L), pH (2−10), dye concentration (5–45 mg/L), contact duration (0–140 min), and shaking speed (100–180 rpm) on the removal (adsorption) efficiency at 23 °C were investigated. Besides the kinetic and isothermal studies were applied as well to improve commercial adsorbents’ performance in removing anionic dyes. Fe3O4 magnetic nanoparticles achieve a maximum azo dye removal (adsorption) efficiency of 99.99% at the optimum values of the investigated parameters: 3 g/L of adsorbent dose, 5 mg/L dye concentration, pH 2, and 180 rpm in 120 min at 23 °C. Langmuir adsorption isotherm has the highest correlation coefficient (R2 = 0.977) compared to Freundlich, and Temkin isotherms; the maximum absorption of azo dye is estimated to be 0.4158 mg/g. The values of the equilibrium parameter (RL) in the Langmuir isotherm model are between 0 and 1, indicating the Langmuir isotherm's favorability. The Fe3O4 magnetic nanoparticle adsorption rates follow pseudo-first-order adsorption kinetics, with R2 = 0.973.

A comparative and comprehensive study on robust silver-immobilized chitosan/carboxy methyl chitosan macromolecules for elimination of dyes

This study explores the potential of modified chitosan (CH) resulting from carboxy methyl (CM) group substitution in the chitosan skeleton, producing carboxy methyl chitosan (CMCH). Silver (Ag) was loaded to chitosan and modified chitosan (carboxy methyl substituted chitosan) supported on cellulose filter paper (FP) to tailor organic–inorganic macromolecule composites “Ag-Chi/CFP and Ag-CMCH/CFP” further applied as substantial composite for the reductive removal of methyl orange (MO) and rhodamine B (RB) dyes from wastewater. The synthesized catalyst was characterized via FTIR, 1H NMR, XRD, and SEM analysis. The degree of substitution was also measured, which was approximately 0.85. The reductive elimination efficiency of Ag-CMCH/CFP and Ag-Chi/CFP for MO dye was 95.31% and 88.85 %. In comparison, the elimination of RB was 98.28 and 94.04 %, respectively, in 16 min time, 0.6 mM Ag concentration, 40 mg/L, dye concentration and 0.3 M NaBH4 concentration. The synthesized catalysts were recycled three times. The degradation of MO and RB dyes using Ag-CMCH/CFP and Ag-Chi/CFP catalysts can be described by the first-order kinetic model. The determination coefficients (R2) and rate constants (k) values for MO degradation were found to be 0.9934 and 0.1736 s−1 for Ag-CMCH/CFP, and 0.9242 and 0.1001 s−1 for Ag-Chi/CFP, respectively. Similarly, for RB degradation, the R2 values were 0.9866 for Ag-CMCH/CFP and 0.9803 for Ag-Chi/CFP, with corresponding k values of 0.219 s−1 and 0.1548 s−1, respectively. The degradation process was optimized using response surface methodology (RSM) to determine the optimal conditions for maximum dye removal efficiency. The RSM models were statistically significant, as validated by ANOVA and correlation coefficient values. The F values of MO and RB models are significant as they have 2450.15 and 21999.37, respectively. The P value for both was <0.0001.

Enhanced visible light-driven photocatalytic activity of green synthesized cobalt ferrite nanoparticles

Cobalt ferrite nanoparticles were synthesized through green synthesis using Erythrina variegata leaf extract. The presence of phytonutrients in the Erythrina variegata leaf extract was confirmed by phytonutrient screening analysis. The thermal, structural, optical, functional, chemical, morphological, and compositional properties of prepared nanoparticles were analysed. The crystal violet (CV) and congo red (CR) dyes eliminated from water using CoFe2O4 NPs as an adsorbent, has been reported. The thermal stability of as-prepared samples was studied by TG-DTA and powder XRD analysis exhibits a cubic inverse spinel structure. By using UV–Vis spectroscopy, the lower band gap energy of CoFe2O4 NPs was found to be around 1.86 eV. The relevant FTIR and Raman spectra indicated Fe–O (tetrahedral site) and Co–O (Octahedral site) band, which attributed to the stretching vibration modes. The cubic-shaped and irregular agglomerated particles was examined from SEM images. The existence of all required elements in prepared CoFe2O4 NPs were confirmed by EDX and XPS analysis. Leaching experiment using the seed germination method for CoFe2O4 catalyst was evaluated. Moreover, the effective photocatalytic performance of crystal violet (CV) and congo red (CR) dye adsorption using CoFe2O4 catalyst within 120 min on the effect of pH, dye dosage, exposure time, and kinetic studies under visible light were investigated. The maximum dye removal efficiency of 85.18 % and 79.58 % was observed using 25 mg/L at pH 9 for CV and CR dyes, respectively. Trapping experiments revealed that O2•− is the major active species in the dye degradation. Recycling experiments revealed good stability after three cycles for CoFe2O4 catalyst. As a result, the prepared CoFe2O4 NPs can be utilized as an effective adsorbent for wastewater treatment.

Adsorptive removal of malachite green dye from aqueous solution using Rumex abyssinicus derived activated carbon

The potential for malachite green dye saturated effluent to severely affect the environment and human health has prompted the search for effective treatment technologies. Thus, this study was conducted with the goal of developing activated carbon from Rumex abyssinicus for the adsorptive removal of malachite green dye from an aqueous solution. Unit operations such as drying, size reduction, impregnation with H3PO4, and thermal activation were used during the preparation of the activated carbon. An experiment was designed considering four main variables at their respective three levels: initial dye concentration (50, 100, and 150 mg/L), pH (3, 6, and 9), contact period (20, 40, and 60 min), and adsorbent dosage (0.05, 0.01, and 0.15 g/100 mL). Optimization of the batch adsorption process was carried out using the Response Surface methodology's Box Behnken approach. The characterization of the activated carbon was described by SEM for surface morphology with cracks and highly porous morphology, FTIR for multi-functional groups O–H at 3506.74 cm−1 and 3290.70 cm−1, carbonyl group stretching from aldehyde and ketone (1900–1700 cm−1), stretching motion of aromatic ring C=C (1543.12 cm−1), stretching motion of –C–H (1500–1200 cm−1), vibrational and stretching motion of –OH (1250.79 cm−1), and vibrational motion of C–O–C (1049.32 cm−1), pHpzc of 5.1, BET for the specific surface area of 962.3 m2/g, and XRD for the presence of amorphous structure. The maximum and minimum dye removal efficiencies of 99.9% and 62.4% were observed at their respective experimental conditions of (100 mg/L, 0.10 mg/100 mL, pH 6, and 40 min) and (100 mg/L, 0.15 mg/100 mL, pH 3, and 20 min), respectively. Langmuir, Freundlich, Toth, and Koble-Corrigan models were used to evaluate the experimental data, in which Koble-Corrigan model was found to be the best fit with the highest value of R2 0.998. In addition to this, the kinetic studies were undertaken using pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Boyd models, and as a result, the pseudo-second-order model proved to have a better fit among the kinetic models. The kinetics and isotherm analysis revealed that the nature of the adsorption to be homogenous and monolayer surfaces driven by chemosorption. Furthermore, the thermodynamics study revealed the nature of adsorption to be feasible, spontaneous, and endothermic. On the other hand, the reusability study depicted the fact that the adsorbent can be utilized for five cycles with a negligible drop in the removal efficiencies from 99.9 to 95.2%. Finally, the low-cost, environmentally benign, and high adsorption capacity of the adsorbent material derived from Rumex abyssinicus stem could be used to treat industrial effluents.

Electrogenic engineered flow through tri-phasic wetland system for azo dye treatment: Microbial dynamics and functional metagenomics

Electrogenic engineered flow through tri-phasic wetland (EEFW) system based on nature-based ecological principles was studied by integrating successive biological microenvironments. The potential mechanism of the plant root-based microbial community and its functional diversity with the influence of plant-microbe-electrode synergism towards dye degradation was evaluated. The EEFW system was operated at three varied dye loads of 10, 25 and 50 mg L−1, where the results from the cumulative outlets revealed a maximum dye removal efficiency of 96%, 96.5% and 93%, respectively. Microbial community analysis depicted synergistic dependence on the plant-microbe-electrode interactions, influencing their functional diversity and metabolism towards detoxification of pollutants. The core microbial taxa enriched against the microenvironment variation were mostly associated with carbon and dye removal viz., Desulfomonile tiedjei and Rhodopseudomonas palustris in Tank 1 and Chloroflexi bacterium and Steroidobacter denitrificans in Tank 2. The degradation of polycyclic aromatic hydrocarbons, chloroalkane/chloroalkene, nitrotoluene, bisphenol, caprolactam and 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) were observed to be predominant in Tank 1. EEFW system could be one of the option for utilizing nature-based processes for the treatment of wastewater by self-induced bioelectrogenesis to augment process efficiency.

Synergistic Effect of Yb3+, Tm3+, Nd3+ Doped NaYF4 Nanoparticles and MoS2 Nanosheets for Enhanced Photocatalytic Dye Degradation under Visible Light

The synergistic influence of synthesized MoS2 (syn-MoS2) nanosheets and NaYF4:Yb,Tm,Nd upconversion nanoparticles (UCNP) on effective dye degradation is demonstrated. A detailed characterization of bulk MoS2 (b-MoS2), syn-MoS2 (with enhanced photocatalytic activity compared to the commercially available b-MoS2), and UCNP was done. Optical properties revealed that emission spectra of UCNP corresponding to 450, 475, and 650 nm overlap with absorption spectra of MoS2 (∼455 and 635 nm). A comparative methylene blue degradation of 96% could be achieved with the combination of UCNP and syn-MoS2 in comparison to 56.4% for syn-MoS2 and 42% for b-MoS2. Concentration-dependent dye degradation study of UCNP and syn-MoS2 revealed a maximum dye removal efficiency of 99.6% for 150 mg L–1 of syn-MoS2 and 200 mg L–1 of UCNP within 2 hrs. Comparative degradation investigations were performed on various dyes (methylene blue, methylene orange, rhodamine B, and their mixture) and water systems (artificial river-water and artificial seawater) to assess the potential applicability of the system in environmental remediation. After five cycles of reusability studies, an efficacy of 88% dye removal was obtained. The mechanism behind this was investigated using the ESR and scavengers test, which confirmed that the primary radicals responsible for dye degradation were superoxide (•O2–) and hydroxyl (•OH). A comparative photocurrent experiment also verified that the presence of UCNP enhances the efficiency of the syn-MoS2 by 98% in the presence of visible light.

Utility of acrylic acid grafted lignocellulosic waste sugarcane bagasse for the comparative study of cationic and anionic dyes adsorption applications

Novel effective and eco-friendly advantageous acrylic acid grafted biosorbent derived from sugarcane bagasse (SB) have been explored for the degradation of cationic (MB and Rh 6G) and anionic (MR) dyes from wastewater. Analytical characterization of manufactured biosorbents was performed. To optimize operational conditions, batch adsorption studies were carried out. Cell-g-AAc is a biosorbent made by grafting acrylic acid onto the cellulose backbone. Dye adsorption as a function of pH, dye concentration temperature and contact time was analyzed. Opting several kinetics and adsorption models, the mechanism of adsorption and interactions between biosorbent Cell-g-AAc and various adsorbates were investigated. The Temkin adsorption isotherm has a larger R2 than the other two adsorption isotherms, indicating that the Temkin adsorption isotherm model better fits the adsorption data for MB and Rh 6g (cationic) dyes, but the adsorption of MR (anionic dye) matched the Langmuir model. The MR (anionic) dye followed a pseudo-first-order kinetic model during adsorption, while the pseudo-second-order model fits better for MB and Rh 6G (cationic) dyes and dye absorption (mg/g) that is substantially nearer to the observed value. Under ideal conditions, cellulose showed maximum dye removal efficiencies of 87.4 %, 90.2 %, and 73.9 % for the MB, Rh 6G, and MR dyes, respectively. The MB, Rh 6G, and MR dyes, on the other hand, showed 92 %, 97.1 %, and 80.6 % for Cell-g-AAc, respectively.

Scale-up factors, kinetics, passivation and sludge analysis for electrochemical removal of malachite green oxalate dye

ABSTRACT A new approach has been proposed to predict the effectiveness of electrocoagulation (EC) process to treat synthetic dye solution containing malachite green oxalate or Basic Green-4 (BG 4). Process intensification was used to optimise the EC operational parameters. Constant current batch galvanostatic studies were carried out under a single-pair Al electrode system at spacing (0.3–2 cm), dipped area (12–31 cm2), current (0.1–0.5 A), time (0–70 min) and dye concentration (10–1000 mg/L). Maximum dye removal efficiency >96 was attained within 10 min of the EC process with dye concentrations ranging from 100 to 1000 mg/L at optimal parameters of 6.98 pH, 0.5 cm spacing, 8 cm dipped length and 17.86 mA/cm2 current density. The dye removal and functional groups were verified by Fourier transform infrared spectroscopy (FTIR) and UV/Vis measurements. The field emission scanning electron microscope (FESEM) results revealed that the sludge containing dye particles included more carbon and small amounts of Na and Cl. According to the atomic force microscopy (AFM) findings, there was evidence of polynuclear aluminium floc production and pitting corrosion. Furthermore, PI values of 0.769 to 1 and 0.328 to 0.443 show that the particles in both EC supernatants are linear polynuclear groups with varying sizes. A linear association with R2 of 0.96 was found in the kinetic analysis between the loading concentration (Ci) and the optimal removal time (ORT). Based on ORT estimates, operating costs (OC) were calculated, and for Ci >806.33 mg/L, EC was determined to be cost-effective.