Treatment Of Dye-containing Wastewater Research Articles

Decolorization and degradation of crystal violet dye by electron beam radiation: Performance, degradation pathways, and synergetic effect with peroxymonosulfate

Ionizing radiation (mainly including gamma ray and electron beam) technology provides a more efficient and ecological option for dye-containing wastewater treatment, which is supported by its successful achievements in industrial-scale applications. However, the degradation pathway of triphenylmethane dyes by radiation technology is still unclear. In this study, crystal violet (CV) was selected as representative cationic triphenylmethane dye, the decolorization and degradation performance by electron beam radiation technology was systematically evaluated. The results showed that CV can be efficiently decolorized and mineralized by radiation, and its degradation kinetics followed the first-order kinetic model. The effect of inorganic anions and chelating agents commonly existed in dye-containing wastewater on CV decolorization and total organic carbon (TOC) removal was explored. Quenching experiments, density functional theory (DFT) calculation and high performance liquid chromatography mass spectrometry (HPLC-MS) analysis were employed to reveal CV decolorization and degradation mechanism and pathway, which mainly included N-demethylation, triphenylmethane chromophore cleavage, ring-opening of aromatic products and further oxidation to carboxylic acid, and mineralization to CO2 and H2O. Additionally, electron beam radiation/PMS process was explored to decrease the absorbed dose required for decolorization and degradation, and the synergetic effect of radiation with PMS was elucidated. More importantly, the findings of this study would provide the support for treating actual dyeing wastewater by electron beam radiation technology.

A novel strategy for preparing high-performance, low-cost biomass charcoal for dye adsorption using aquatic agricultural waste lotus stem fibers

In this study, lotus stem (LS), a natural, abundant, and underutilized aquatic agricultural waste, was used to prepare biochar (BC) as a potential adsorbent for sewage treatment. A two-step process for the production of LS based nitrogen-doped BC (NLBC) has been developed, involving low-temperature pyrolysis of LS and urea mixture, followed by high-temperature pyrolysis of the pre-carbonized BC via NaOH immersion technique. The two-step activation treatment not only can effectively maintain the structural integrity of LS, but contribute to exposing more active sites for effective adsorption of methylene blue (MB). The obtained NLBC possesses a large pore volume (0.997 cm3 g−1) and great specific surface area of 1478.93 m2 g−1, contributing to its maximum adsorption capacity of 2320.81 mg g−1 for MB. The behavior of MB adsorbed onto NLBC conforms to pseudo-second-order kinetics and Langmuir–Freundlich models. The adsorption capacity remains stable across a range of pH, varying salt concentrations, and cyclic repetitions. The adsorption mechanism was ascribed to the synergetic effects of pore filling, H-bonding, and electrostatic interaction through comparative analysis before and after adsorption. The results indicate that NLBC is an environmentally friendly, cost-effective, and efficient for dye-containing wastewater treatment.

Polyethersulfone-silica aerogel/ polypyrrole solar evaporation membrane for wastewater treatment and desalination

Solar interfacial evaporation utilizes a specific structure of the evaporator to confine the energy to the light absorbing layer, so that the water completes efficient evaporation on the surface of the structure. In this paper, polyethersulfone- silica aerogel/ polypyrrole solar evaporation membranes (PES-SiO2/PPy) with excellent photo-thermal conversion and efficient seawater desalination performance were prepared by loading PPy on polyethersulfone-silica aerogel ultrafiltration membranes (PES-SiO2) via in situ polymerization. With its stable and efficient thermal insulation performance and heat absorption ability, the temperature on the surface of the evaporation membrane was as high as 49.9 °C under 1 kW m−2 light intensity, and the maximum evaporation rate reached 1.86 kg m−2 h−1, with an evaporation efficiency of 97%. The evaporation membranes also have long-term stable evaporation performance. At an outdoor light intensity of 0.8 kW m−2, the evaporation rate of simulated seawater reached 1.87 kg m−2 h−1 with a high evaporation efficiency of 131.6%, which can be realized for highly efficient desalination and dye-containing wastewater treatment with the aid of ambient energy. The present work demonstrates the efficient solar evaporation performance of ultra-low-cost evaporation membranes with the prospect of large-scale water purification treatment.

Sustainable approach for the treatment of dye-containing wastewater – a critical review

Abstract In the world’s rapidly expanding economy, textile industries are recognized as a substantial contributor to economic growth, but they are one of the most significant polluting industrial sectors. Dye-contaminated water sources can pose serious public health concerns, including toxicity, mutagenicity, and carcinogenicity among other adverse health effects. Despite a limited understanding of efficacious decolorization methodologies, the pursuit of a sustainable strategy for the treatment of a wide spectrum of dyes remains a formidable challenge. This article conducted an exhaustive review of extant literature pertaining to diverse physical, chemical, biological, and hybrid processes with the aim of ascertaining their efficacy. It also elucidates the advantages and disadvantages, cost considerations, as well as scalability impediments of the treatment methodologies, thereby facilitating the identification of optimal strategies for establishing techno-economically efficient processes in the sustainable handling of these effluents. The hybrid configuration exhibited superior efficiency and was documented to surmount the limitations and constraints inherent to individual techniques. The study also revealed that most of the proven and established dye removal techniques share a common limitation viz., the generation of secondary pollution (i.e., sludge generation, toxic intermediates, etc.) to the ecosystem.

Activity and recyclability enhancement of pH-dependent Fe0@BC-mediated heterogeneous sodium percarbonate (SPC)-reducing agents (RA) system

Dyes pose great threats to the aquatic environment and human health. Fe0-based Fenton-like systems have been widely employed for the degradation of organic dyes. However, the regulation of degradability and recyclability was still unclear. In this study, Rhodamine B (RhB) was served as the model pollutant, hydroxylamine hydrochloride was selected as the RA, the natural photocatalysis system demonstrated stable operation. RA, as performance enhancement agent, was firstly reported in micro/nano-Zero-Valent Iron@Biochar (m/nZVI@BC) based SPC-RA system. Carrier size-fractionated m/nZVI@BC was fabricated by one-step carbothermal method. As a result, RA synergistically interacted with SPC, and the reaction time reduced from 15 min to 4 min. In the 0.010 g m/nZVI@BC-mediated SPC-RA system, over 95% of RhB (100 mg·L−1, 1041.667 mg·g−1) was successfully degraded. The maximum degradation ability could still exceed 1g·g−1 via 5 times repeated applications. Meanwhile, the loss of degradability, caused by halving SPC concentration could be compensated by RA dosage measurement. The entire degradation process was predominantly dominated by free radicals (•OH> 1O2> •O2−> •CO3−). Reactive oxidizing species (ROSs) were primarily excited by α-Fe0, Fe3C and N sites of biochar (BC). Light and BC carrier dedicated slight influence. These discoveries shed a light on the activity and recyclability regulation of catalytic material, aligning with the principles of green chemistry and cleaner production. This study demonstrates a novel approach to efficient management of solid waste disposal, reuse of waste biomass, advanced treatment of dye-containing wastewater, pollution control in aquatic environments.

Ferrocene crosslinked and functionalized chitosan microspheres towards bio-based Fenton-like system for the removal of organic pollutants

Dye-containing wastewater treatment has been a major long-term global challenge. For this purpose, a novel bio-based microspheres (CS-FC) with high specific surface area (63.24 m2·g−1) and nano-channels (17.95 nm) was prepared using chitosan as the framework and ferrocene as a crosslinking active group. CS-FC not only has the ability to rapidly enrich methyl orange (MO) through hydrogen-bonding and electrostatic attraction, but also almost completely degrades it in the presence of H2O2/K2S2O8 through a synergistic radical/non-radical mechanism under the activating effect of ferrocene. Without H2O2/K2S2O8, the maximum MO adsorption capacity of CS-FC is in the range 871–1050 mg·g−1, and conforms to a Langmuir isothermal model with pseudo-second-order kinetics. In the presence of H2O2/K2S2O8, the removal of MO dramatically increased from 32 % to nearly 100 % after incubation for 60 min, due to the simultaneous formation of highly reactive 1O2 and ·OH. The significant contribution from 1O2 endowed CS-FC/H2O2/K2S2O8 with high universality for degrading various organic pollutants (including azo dyes and antibiotics), a wide pH window (2–8), and low sensitivity to co-existing ions. Such cost-effective, recyclable porous bio-based microspheres are suitable for heterogeneous Fenton-like catalysis in organic wastewater treatment that rely on synergistic radical/non-radical reaction pathways.

Synergism of Artificial Intelligence and Techno-Economic for Sustainable Treatment of Methylene Blue Dye-Containing Wastewater by Photocatalysis

Recently, removing dyes from wastewater by photocatalysis has been extensively studied by several researchers. However, there exists a research gap in optimizing the photocatalytic process parameters using artificial intelligence to maintain the associated techno-economic feasibility. Hence, this investigation attempts to optimize the photocatalytic degradation of methylene blue (MB) dye using an artificial neural network (ANN) model to minimize the capital and running costs, which is beneficial for industrial applications. A ZnO/MgO photocatalyst was synthesized, showing an energy band gap of 2.96 eV, crystallinity index of 71.92%, pore volume of 0.529 cm3/g, surface area of 30.536 m2/g, and multiple surface functional groups. An ANN model, with a 4-8-1 topology, trainlm training function, and feed-forward back-propagation algorithm, succeeded in predicting the MB removal efficiency (R2 = 0.946 and mean squared error = 11.2). The ANN-based optimized condition depicted that over 99% of MB could be removed under C0 = 16.42 mg/L, pH = 9.95, and catalyst dosage = 905 mg/L within 174 min. This optimum condition corresponded to a treatment cost of USD 8.52/m3 cheaper than the price estimated from the unoptimized photocatalytic system by ≈7%. The study outputs revealed positive correlations with the sustainable development goals accompanied by pollution reduction, human health protection, and aquatic species conservation.

Multifunctional amphibious superhydrophilic-oleophobic cellulose nanofiber aerogels for oil and water purification

Aerogels are of a popular choice for oil-water separation and water purification due to their attractive properties, such as lightweight, large surface area, and high porosity. Developing robust aerogels with multifunctional characteristics is highly desirable but remains challenging nowadays. Herein, we develop a facile one-pot condensation strategy for the fabrication of superhydrophilic-oleophobic (SHI-OP) composite aerogels using cellulose nanofibers (CNF), 3-glycidy-loxypropyl trimethoxysilane (GPTMS), polyethyleneimine (PEI) and fluorine-contained compound (FS-60). The resulted aerogels exhibit a directional lamellar structure with interconnected macropores, super-lightweight with high porosity of 98.30 % and low density of 0.0256 g·cm−3. Also, the aerogels are mechanically durable against repeated compression. Meanwhile, the amphibious SHI-OP feature of the composite aerogels in both air and water states enables them to not only absorb trace amount of water from contaminated oils, but also separate oil-water mixtures with separation efficiency of over 99 % and high permeation flux of over 9060 L/m2·h. Moreover, the aerogels also show excellent dye adsorption capability and reusability toward anionic dyes with a maximum adsorption capacity of 1245.68 mg/g. Such robust and multifunctional aerogels with special surface wettability provide good opportunity for liquid purification and dye-containing wastewater treatment.

Magnetic chitosan-functionalized waste carton biochar composites for efficient adsorption of anionic and cationic dyes

In this study, BC-CoFe2O4-CS magnetic composite was successfully prepared from waste cardboard and investigated as an efficient adsorbent for the removal of amaranth and methyl orange in aqueous solution. First, the fibers obtained from the cardboard waste were carbonized by a hydrothermal process to produce biochar. Subsequently, the final magnetic composites were synthesized by in situ growth and Schiff base crosslinking reactions. The composites were characterized by zeta potential, Brunauer–Emmett–Teller measurements, Fourier transform Infrared spectroscopy, Scanning electron microscopy, Energy dispersive spectrometer,X-ray Diffraction, Thermogravimetry analysis and Vibrating sample magnetometer. The effects of adsorbent dosage and initial solution pH on dye removal efficiency were studied. The results showed that the maximum adsorption capacity of amaranth could reach 500.6 mg·g−1 at pH = 2, the adsorbent dosage of 0.5 mg·ml−1, and methyl orange could reach 644.0 mg·g−1 at pH = 4, the adsorbent dosage of 0.5 mg·ml−1. The adsorption process followed the pseudo-second order kinetic models and Langmuir isotherm. BC-CoFe2O4-CS was easily separated from the aqueous solution due to the loading of CoFe2O4 magnetic nanoparticles. Besides, the BC-CoFe2O4-CS could be further used after the adsorption experiments with or without desorption and still showed good adsorption performance in the actual water samples. Therefore, it is expected that the composite material prepared from waste cartons can be used for the treatment of dye-containing wastewater due to its low cost, high efficiency, and simple application.

Engineering a separation membrane containing a gel layer with backbone support effect and bionic-inspired capillary effect for the efficient separation of dyes/salts

Accurate separation of dyes/salts is a crucial step in the treatment of dye-containing wastewater. Therefore, separation membranes with high permeability and high dye/salt selectivity are urgently required. In this study, an ultrathin gel layer of carboxymethyl cellulose was constructed on a poly(vinylidene fluoride) membrane surface. This gel layer contains a backbone support structure and provides the bionic-inspired capillary effect, which endows the membrane with the capability to realize the efficient separation of dyes and salts. The introduction of silver nanoparticles (Ag NPs) into the gel layer provides a skeleton support structure, which prevents the collapse of the gel layer, reduces the actual separation layer thickness, and decreases the mass transfer resistance. Moreover, the formation of capillaries between the numerous Ag NPs facilitates the rapid penetration of water molecules. Interestingly, this membrane exhibited excellent selectivity for dye/salt separation (dye removal >99.5 %, salt removal <10 %) while maintaining an exceptionally high water permeate flux (244.5 L/m2h). Moreover, the membrane exhibited excellent stability. This study demonstrates that the construction of organic/inorganic three-dimensional structures with capillary and skeletal support effects show promise potential for modification of dye/salt separation membranes.

A novel bioflocculant extracted from excess-activated sludge for dye-containing wastewater treatment

Textile dyes are a major environmental concern related to the textile industry field due to their chemical complexity that hampers biodegradability and constraints conventional wastewater treatment. In this context, this work presents a bioflocculant produced from textile industry excess-activated sludge capable of precipitating azo dyes. The alkaline hydrolysis employed on dried activated sludge was optimized and the produced bioflocculant was characterized in terms of chemical composition, SEM-EDX, TEM, XRF, AAS, and TGA. The resulting flocculant presented 27 % protein, 12 % carbohydrate, and 12 % lipid contents, with hydroxyl and aliphatic CH functional groups. The chemical structure of dyes, the pH, and the respective zeta potential of the flocculating medium were taken into consideration during assays to conclude the flocculation mechanism. Flocculation assays resulted in color removal outcomes of 91 and 100 % for reactive and disperse dyes, respectively, at pH 5, and the OECD 301A biodegradability test confirmed the low presence of cellular debris after treatment. The activity of the bioflocculant was evaluated with a commercial naphthalene-based dispersant and the results were compared to color removal promoted by polyaluminum chloride (PAC). This work shows the feasibility of the low-cost activated sludge as a bioflocculant source and its potential in clarifying wastewater with azo dyes.

Removal of methyl orange textile dye using magnetic chitosan microspheres adsorbent

Abstract Industrial textile wastewater contains high levels of dyes, which are potentially harmful to aquatic ecosystems by inhibiting sunlight penetration for photosynthesis activities. Adsorption is a simple method for pollutant removal for water treatment. Magnetic Chitosan Microspheres (MCM) has been developed as a natural adsorbent for dye removal. This study aimed to compare the properties of the raw adsorbent and after adsorption by FT-IR, BET, DLS, and SQUID Magnetometry. The adsorption behaviours were investigated by the influence of pH, contact time, and initial concentration on Methyl Orange removal. The result was MCM could eliminate MO until 93.60% at pH 7 with C0 100 mg L−1 in 5 min with an adsorption capacity of 187.21 mg g−1. Adsorption processes were also studied through the isotherm and kinetic. The isotherm showed a closer fit to the Langmuir model than the Freundlich model. The kinetic result showed the PSO model was more suitable than PFO. The research data using MCM for adsorption demonstrated excellent adsorption capability in terms of dye removal percentage and high adsorption capacity. Therefore, this material could be an effective adsorbent for the treatment of dye-containing wastewater.

Highly efficient removal of tetracycline and methyl violet 2B from aqueous solution using the bimetallic FeZn-ZIFs catalyst

Abstract Residual antibiotics and organic dyes in wastewater have gained the current challenge all over the world because of their toxicity to humans and the environment. In this study, the bimetallic porous FeZn-ZIFs materials were successfully prepared under mild conditions at room temperature and atmospheric pressure and characterized by various techniques. The FeZn-ZIFs were used as a heterogeneous catalyst to remove tetracycline antibiotics (TC) and methyl violet 2B dyes (MV) in an aqueous solution by activating peroxymonosulfate (PMS) and peroxydisulfate (PDS), respectively. The catalytic activity of FeZn-ZIFs towards TC and MV under different oxidant dosages, the catalyst dosage, the initial pollutant concentration, contact time, and reaction temperature were optimized. The results indicated that FeZn-ZIFs was an efficient catalyst for removing TC and MV based on advanced oxidant processes, having a removal capacity of 92% at TC concentration of 50 mg·L−1 and 95% MV concentration of 20 mg·L−1. More importantly, this bimetallic catalyst was identified the superior structural stability when the removal efficiency of TC and MV was maintained at approximately 90% after five cycles. In short, the FeZn-ZIFs and PMS/PDS system exhibited a promising application prospect for antibiotic and dye-containing wastewater treatment.

Comparing biofilm reactors inoculated with Shewanella for decolorization of Reactive Black 5 using different carrier materials.

This study assessed the performance of biofilm reactors inoculated with azo dye degrading Shewanella for the decolorization of Reactive Black 5 (RB5), using three different carrier materials, namely almond shell biochar, moving bed biofilm reactor (MBBR), and polypropylene carrier (PPC). The reactors were fed with low-nutrient artificial wastewater containing RB5, and all three carriers showed good RB5 decolorization performance, with varying efficiencies. Liquid Chromatography-Mass Spectrometry analysis revealed distinct RB5 degradation pathways associated with each carrier, influenced by carrier materials and microbial communities. The MBBR carrier exhibited good stability due to its rough surface and microbial aggregates. Sequencing results highlighted differences in the microbial community structures among the carriers. Shewanella predominated the functional bacteria in the MBBR and PPC carriers, while the biochar carrier fostered highly efficient degrading microbial communities. The physicochemical properties of carrier materials significantly influenced the microbial community and RB5 degradation efficiency. These findings provide valuable insights for optimizing biofilm reactors for dye-containing wastewater treatment.

Preparation of agar functionalized graphene oxide-immobilized copper ferrite aerogel for dye degradation via dark-Fenton oxidative process

Dye and textile industries are one of the main causes of water pollution and put the environment and health of society at risk. Developing new materials to decontaminate industrial waste effluents containing dyes as pollutants is challenging due to numerous issues, including tailoring recyclable and biodegradable agents. This study focuses on applying an advanced oxidation process, electro-Fenton for the treatment of dye-containing wastewater using agar-functionalized graphene oxide-immobilized copper ferrite aerogel. The objective is therefore to determine the optimal conditions for the degradation of model pollutants methylene blue (MB). MB was oxidized and degraded through the dark-Fenton process using Agar@GO-CuFe2O4 as a new biobased catalyst. The effect of the operating parameters was then evaluated to determine the optimal conditions. The degradation process was screened for different initial concentrations of dye solution between 10 and 150 mg/l, a volume range of H2O2 between 0.5 and 2.5 ml, and different pH from 2 to 7. The results show that 99.89 % of the MB with the initial concentration of 150 ppm was degraded by 20 mg of the catalyst and 2 ml of H2O2 (30 % W/W) at 40 °C and pH = 6. Pseudo-second-order kinetics satisfactorily describes the experimental data. SynopsisThe prepared catalyst can be applied to oxidize industrial effluents before they are released into the environment.

Photo-induced adsorption-desorption behavior of methylene blue on CA-BMO under visible light irradiation.

In this work, the modification of Bi2MoO6 with critic acid (CA-BMO) to achieve enhanced adsorption of methylene blue (MB) solution in dark and desorption under visible light irradiation was reported. The as-prepared materials were synthesized by a hydrothermal method and characterized via SEM, FT-IR, XRD, and XPS techniques. Only 16.5% of 10mg L-1MB was removed within 10min by using 0.5g L-1 Bi2MoO6, while 92.9% removal of MB could be achieved by using 0.5g L-1 CA-BMO, which enhanced the adsorption removal by a factor of 4.6. The adsorption capacity for MB was 18.9mgg-1. Desorption efficiency of MB was only observed in CA-BMO system, and it depends on the wavelength of the light source, pH, and the presence of metal ions. Characterization results suggested that carboxyl groups, which were modified onto the surface of Bi2MoO6, could serve as adsorption sites for MB, and the connections were damaged under light, thus leading to the desorption of MB from the surface of the CA-BMO. This study provides a novel reagent-free desorption strategy for dye recovery without secondary pollution, which facilitates the development and application of Bi-based adsorbent for dye-containing wastewater treatment.

Anaerobic biodegradation of anthraquinone dye reactive black 19 by a resuscitated strain Bacillus sp. JF4: Performance and pathway

Anthraquinone dyes are known for their resistant nature and challenging biodegradation in harsh environmental conditions. In this study, the potential of a resuscitated strain Bacillus sp. JF4 for degrading the refractory anthraquinone dye Reactive Blue 19 (RB19) was investigated. The results demonstrated that JF4 was capable of effectively degrading RB19 using glucose and peptone as co-substrates at 3 g/L each. Notably, JF4 exhibited excellent RB19 biodegradation over a broad pH range (7−9) and NaCl concentrations (0–40 g/L). Under optimal conditions of pH 7.0 and 30 °C, JF4 efficiently degraded RB19 at concentrations of 25–150 mg/L, achieving almost complete degradation of 125 mg/L RB19 within 184 h. The biodegradation process of high RB19 concentrations (75–150 mg/L) by JF4 followed a first-order kinetic model, with an increasing half-life (t1/2) as RB19 concentration rises. Enzyme activity analysis revealed significant induction of lignin peroxidase, indicating its active role in RB19 biodegradation. The degradation pathways of RB19 by JF4 were proposed based on the analysis of metabolites and enzymes, involving reductive cleavage of RB19 followed by further degradation through oxidoreductive enzymes. These findings highlighted the high-efficient RB19-degrading capability of the resuscitated strain JF4 with remarkable alkalinity and salinity tolerance, providing new insights for cultivating effective bio-inoculants in the treatment of anthraquinone dye-containing wastewater.

Alkaline-thermal hydrolysate of waste activated sludge as a co-metabolic substrate enhances biodegradation of refractory dye reactive black 5

Aromatic azo dyes possess inherent resistance and are known to be carcinogenic, posing a significant threat to human and ecosystems. Enhancing the biodegradation of azo dyes usually requires the presence of co-metabolic substrates to optimize the process. In addressing the issue of excessive waste activated sludge (WAS) generation, this study explored the potential of utilizing alkaline-thermal hydrolysate of WAS as a co-metabolic substrate to boost the degradation of reactive black 5 (RB5) dyes. The acclimated microbial consortium, when supplemented with the WAS hydrolysate obtained at a hydrolysis temperature of 30 °C, achieved an impressive RB5 decolorization efficiency of 90.3% (pH = 7, 35 °C) with a corresponding COD removal efficiency of 45.0%. The addition of WAS hydrolysate as a co-substrate conferred the consortium with a remarkable tolerance to high dye concentration (1500 mg/L RB5) and salinity levels (4–5%), surpassing the performance of conventional co-metabolic sugars in RB5 degradation. 3D-EEM analysis revealed that protein-like substances rich in tyrosine and tryptophan, present in the WAS hydrolysate, played a crucial role in promoting RB5 biodegradation. Furthermore, the microbial consortium community exhibited an enrichment of dye-degrading species, including Acidovorax, Bordetella, Kerstersia, and Brevundimonas, which dominated the community. Notably, functional genes associated with dye degradation and intermediates were also enriched during the RB5 decolorization and biodegradation process. These findings present a practical strategy for the simultaneous treatment of dye-containing wastewater and recycling of WAS.

Activated charcoal modified BaFe12O19 powder: a recyclable magnetic adsorbent for removal of methyl blue dye from aqueous solutions

ABSTRACT Use of sophisticated adsorbent materials to clean harmful dye-contaminated water is rapidly gaining popularity. Among different adsorbent, magnetic ferrites based adsorbent are gaining much attention because of their easy recyclability. In this current work, activated charcoal (AC) modified magnetic BaFe12O19 (BaM) ferrite-based novel adsorbent (BaM-AC) powder was synthesised through a sol-gel combustion route. As a model dye pollutant, methyl blue (MB) was used to estimate the adsorption efficiency of BaM-AC adsorbent. X-ray diffraction (XRD) was utilised to analyse pure BaM and BaM-AC powder phases. Fourier transform infrared spectroscopy (FTIR), Brunauer, Emmett and Teller (BET), vibrating sample magnetometer (VSM) and field emission scanning electron microscope (FESEM) were also used for the characterisation of prepared adsorbents. The surface area of BaM-AC powder determined by BET was 5.93 m2 g−1. The BaM-AC adsorbent has a saturation magnetisation (Ms) of 56.8 emu g−1 and a coercive field (Hc) of 5176 Oe. Microstructural analysis showed the porous morphology of the material. In-depth studies with BaM-AC powder investigated how pH, adsorbent dose, adsorption period, MB dye concentration, and effect of temperature affected MB dye adsorption. Conferring to the outcomes of the MB-adsorption experiment, the equilibrium was reached after around 45 minutes. Pseudo-second-order kinetics and the Sips isotherm model govern the adsorption process. BaM-AC powder exhibited a good recyclability up to five-regeneration cycle. These outcomes suggest that the composite material has the potential to serve as an effective adsorbent for dye-containing wastewater treatment.

Nano structured silver particles as green catalyst for remediation of methylene blue dye from water

Abstract Anthropogenic dyes are one of the major pollutants often found in industrial wastewater. They are very stable as they contain robust aromatic moiety and are highly hazardous to human health and livelihood. There are several methods for the treatment of dye-containing wastewater. However, these techniques have severe limitations in terms of cost, the time required, and the generation of secondary waste. In this regard, silver nanoparticle-based catalysts can prove to be highly useful. In the present study, silver nanoparticles were synthesized by a green method, and the condition of synthesis was optimized by varying different parameters such as the concentration ratio of metal salt and plant extract, temperature, and pH of the reaction medium. The biogenic silver nanoparticles can act as a catalyst in the reductive degradation reaction of an anthropogenic dye (methylene blue) in the presence of sodium borohydride. The synthesized nanoparticles were highly active against methylene blue and degraded the dye within a few minutes. Thus, this work represents a very stable and efficient system for dye-containing wastewater treatment.