Detoxification Of Chromium Research Articles

Wood biochar induced metal tolerance in Maize (Zea mays L.) plants under heavy metal stress

Due to metal toxicity, widespread industrialization has negatively impacted crop yield and soil quality. The current study was aimed to prepare and characterize biochar made from wood shavings of Pinus roxburghii and to determine the plant growth promoting and heavy metal detoxification of cadmium (Cd) and chromium (Cr) contaminated soil. FTIR SEM coupled with EDX characterization of biochar was performed; Cd and Cr were used at a rate of 20 mg/kg. Biochar was used at the rate of 50 mg/kg for various treatments. The completely randomized design (CRD) was used for the experiment and three replicates of each treatment were made. Various agronomic and enzymatic parameters were determined. The results indicated that all growth and enzymatic parameters were enhanced by the prepared biochar treatments. The most prominent results were observed in treatment T5 (in which shoot length, root length, peroxidase dismutase (POD), superoxide dismutase (SOD) catalyzes (CAT), and chlorophyll a and b increased by 28%, 23%, 40%, 41%, 42%, and 27%, respectively, compared to the control). This study demonstrated that biochar is a sustainable and cost-effective approach for the remediation of heavy metals, and plays a role in plant growth promotion. Farmers may benefit from the current findings, as prepared biochar is easier to deliver and more affordable than chemical fertilizers. Future research could clarify how to use biochar optimally, applying the minimum amount necessary while maximizing its benefits and increasing yield.

Ultraviolet-enhanced detoxification of chromate and protection of Brassica napus by Aspergillus sojae SH 20

The pervasive issue of heavy metal contamination in agricultural lands poses significant concerns and has wide-ranging implications for ecosystems. However, an encouraging solution lies in exploiting the potential of fungal endophytes to alleviate these detrimental effects. This study emphasized on improving the growth-promoting and chromium-alleviating capabilities of fungal endophytes, particularly Aspergillus sojae strain SH20, through ultraviolet (UV) irradiation. Following UV treatment, SH20 exhibited significantly enhanced growth-promoting and chromium-alleviating capabilities in comparison to its non-irradiated counterpart. Distinctly, the UV-treated SH20 strain demonstrated an improved ability to accumulate and reduce toxic chromate in the soil, effectively addressing the growth constraints imposed by elevated chromium levels in Brassica napus L. The UV-irradiated SH20 variant boosted shoot length up to 3 times that of the control. Similarly, this fungal strain displayed a remarkable increase in the total fresh weight of the seedlings, recording nearly 17 times greater than the control. The isolate treated with UV light reduced the absorption of chromium by about 3 times in the roots, helping the young plants to grow well even when exposed to chromate stress. A drop in root colonization by the UV-treated strain further resulted in reduced chromate absorption by the roots. Also, the strain showed great skill in boosting the host's antioxidant defenses by reducing the buildup of harmful reactive oxygen species (ROS), increasing the removal of ROS, and improving the plant's antioxidant levels, including phenols and flavonoids. When the host plants were exposed to 25 ppm of Cr stress, the UV-irradiated variant SH 20 stimulated the production of flavonoids (246 μg/ml) and phenols (952 μg/ml) in comparison to the control (with 220 μg/ml of flavonoids and 919 μg/ml of phenols). In conclusion, this report highlights how exposing the A. sojae strain SH20 to UV light has the potential to enhance its abilities to promote growth and bioremediate. This suggests a promising solution for addressing heavy metal contamination in agricultural lands.

Hexavalent Chromium Detoxification by Biochars: Influences of Organic and Inorganic Electron Donors

Hexavalent Chromium Detoxification by Biochars: Influences of Organic and Inorganic Electron Donors

Chromate-induced methylglyoxal detoxification system drives cadmium and chromate immobilization by Cupriavidus sp. MP-37

The detoxification of cadmium (Cd) or chromium (Cr) by microorganisms plays a vital role in bacterial survival and restoration of the polluted environment, but how microorganisms detoxify Cd and Cr simultaneously is largely unknown. Here, we isolated a bacterium, Cupriavidus sp. MP-37, which immobilized Cd(II) and reduced Cr(VI) simultaneously. Notably, strain MP-37 exhibited variable Cd(II) immobilization phenotypes, namely, cell adsorption and extracellular immobilization in the co-presence of Cd(II) and Cr(VI), while cell adsorption in the presence of Cd(II) alone. To unravel Cr(VI)-induced extracellular Cd(II) immobilization, proteomic analysis was performed, and methylglyoxal-scavenging protein (glyoxalase I, GlyI) and a regulator (YafY) showed the highest upregulation in the co-presence of Cd(II) and Cr(VI). GlyI overexpression reduced the intracellular methylglyoxal content and increased the immobilized Cd(II) content in extracellular secreta. The addition of lactate produced by GlyI protein with methylglyoxal as substrate increased the Cd(II) content in extracellular secreta. Reporter gene assay, electrophoretic mobility shift assay, and fluorescence quenching assay demonstrated that glyI expression was induced by Cr(VI) but not by Cd(II), and that YafY positively regulated glyI expression by binding Cr(VI). In the pot experiment, inoculation with the MP-37 strain reduced the Cd content of Oryza sativa L., and their secreted lactate reduced the Cr accumulation in Oryza sativa L. This study reveals that Cr(VI)-induced detoxification system drives methylglyoxal scavenging and Cd(II) extracellular detoxification in Cd(II) and Cr(VI) co-existence environment.

Kinetic studies and bioremediation potential of chromate reductase-characterized Aspergillus flavus from tannery effluent

Chromium is among the major environmental pollutants endangering the health of all living things, including humans. Conventional methods for chromium detoxification are expensive, so bioremediation using fungi as potential agents for the detoxification of chromium is justified. This study aims to investigate chromium-resistant fungi capable of reducing or transforming Cr (VI) to less toxic Cr (III) from tannery effluents. The fungi were isolated from tannery wastewater and identified using 16S rRNA gene sequencing. Chromate reductase was isolated from pure fungal isolate and purified using molecular weight estimation and gel filtration chromatography. Aspergillus flavus, in an interesting turn of events, demonstrated 97% chromate reduction. The chromate reductase from Aspergillus flavus has KM of 0.015 mM and a Vmax of 0.25 mol/min. Furthermore, the enzyme's activity was constant at its peak at pH 7.0 and 50 oC, with a single band displaying a molecular weight of 44 kDa for a pure protein. The data suggest that A. flavus can be a good candidate for the detoxification of Cr (VI) in industrial effluents. The efficiency of which can be attributed to the action of chromate reductase in the A. flavus.

Hexavalent chromium (Cr+6) detoxification potential and stress response of fungus Talaromyces pinophillus isolated from tannery wastewater

Hexavalent chromium (Cr+6) detoxification potential and stress response of fungus Talaromyces pinophillus isolated from tannery wastewater

Hexavalent chromium detoxification by haloalkaliphilic Nesterenkonia sp strain NRC-Y immobilized in different matrices

To develop a bioprocess for Cr(VI) detoxification in industrial effluents, a previously isolated potent Cr(VI) reducing haloalkaliphilic Nesterenkonia sp strain NRC-Y was immobilized and investigated for Cr(VI) detoxification. The immobilization matrices included; natural, modified natural, synthetic, and mixtures of natural and synthetic polymers. Among the tested matrices and immobilization approaches, strain NRC-Y cells encapsulated in 1.5% (w/v) amidated pectin beads exhibited the highest Cr(VI) reduction efficiency (47.02% of initial Cr(VI) concentration 150 mg/L after 20 h) followed by alginate (34.4%), alginate-PVA-chitosan (29.6%), alginate-PVA (25.1%), PVA-PVP (23.2%), and PVA (9.5%). Chromate reductase enzyme was poorly immobilized by covalent binding on the tested materials. Therefore, entrapment in amidated pectin was selected for further investigation and immobilization of both whole cells and partially purified chromate reductase. Operational stability study revealed that the immobilized cells were more efficient and stable than the immobilized chromate reductase, and the free cells. For instance, about 60%, 27.0% and 11.5% of these samples initial activities were retained after four successive batches, respectively. The temperature and pH optima for the immobilized cells were 35°C and 7.0, respectively. The pH and thermal stability of strain NRC-Y cells were significantly enhanced upon immobilization in amidated pectin beads by up to 2.3- and 1.4-fold, respectively. The developed immobilized biocatalyst was applied for Cr(VI) reduction in industrial effluent samples, and it completely reduced Cr(VI) within 4 and 8 h for effluents of initial Cr(VI) concentrations 10 and 30 mg/L, respectively. The developed immobilized biocatalyst is promising and has the potential for large-scale Cr(VI) detoxification application.

Investigation of phytoextraction and tolerance capacity of Calotropis procera for the detoxification of hexavalent chromium, nickel, and lead

The aim of the present study is to reveal the phytoremediation capability of Calotropis procera in the selected region of Bandhwari landfills. Results affirmed that the excessive deposition of municipal solid waste changes the physico-chemical parameters of the soil, which may cause soil pollution. The pot experiment was set up for heavy metals (Cr, Ni, and Pb) analysis with three different concentrations (50 ppm,100 ppm, and 150 ppm). Samples were analyzed to assess the plant’s capability for phytoremediation after 42 days. In the current investigation, ICP-MS results revealed that chromium, nickel, and lead concentration is higher than the permissible limit as per WHO. Results showed that the bioaccumulation factor follows the order of Cr > Ni > Pb. The bioconcentration factor and translocation factor are 15.63 mg/kg and 11.36 mg/kg respectively for Calotropis procera and the highest among all other metal concentrations. Peroxidase activity increases with an increase in chromium ion concentration whereas comparatively less increase of peroxidases in different concentrations of lead and nickel. Peroxidase enzyme assay and photosynthetic pigment test were carried out for tolerance estimation and uptake mechanism of Calotropis procera. FTIR data revealed significant levels of chromium complexation and binding to Calotropis procera tissue via hydroxyl and carboxyl groups. Therefore, it can be concluded that Calotropis procera has the efficiency to provide an effective way to handle heavy metal pollution problems and act as an important cost-effective tool for sustainability and conservation of the environment.

Lignin-coordinated highly dispersed Pd[sbnd]Zn alloy nanocluster supported on N-doped nanolayer carbon and its application in hexavalent chromium detoxification

As a renewable and low-cost biomacromolecule with high aromaticity and carbon content, lignin is a promising raw material for preparation of versatile carbon materials. Herein, we present a facile one-pot approach to prepare PdZn alloy nanocluster catalysts supported on N-doped lignin-derived nanolayer carbon through facile pyrolysis of melamine-mixed lignin-Pd-Zn complex. The dispersion of the PdZn alloy nanoclusters could be effectively modulated by varying the addition of melamine and the molar ratio of Pd and Zn salts. PdZn alloy nanocluster catalysts (Pd-Zn29@N10C) with ultra-small particle size (about 0.47 nm) were prepared when 10 times of melamine (relative to lignin weight) was added and the molar ratio of Pd and Zn salts was 1:29. Thereby, the catalyst presented superior catalytic activity for reduction of Cr(VI) to harmfulless Cr(III), significantly better than the two references Zn@N10C (without Pd addition) and Pd-Zn29@C (without N doping), as well as the commercial Pd/C. In addition, thanks to the strong anchoring of the PdZn alloy on the N-doped nanolayer support, the Pd-Zn29@N10C catalysts also exhibited good reusability. Consequently, the current study provides a straightforward and feasible method for producing highly dispersed PdZn alloy nanoclusters by lignin coordination, and further demonstrates its excellent applicability in hexavalent chromium reduction.

Sustainable production of wurtzite Zinc Sulphide nanocatalyst for detoxification of hexavalent chromium in water and their antibacterial and antioxidant activity

Sustainable production of wurtzite Zinc Sulphide nanocatalyst for detoxification of hexavalent chromium in water and their antibacterial and antioxidant activity

Bioreduction of hexavalent chromium via Bacillus subtilis SL-44 enhanced by humic acid: An effective strategy for detoxification and immobilization of chromium

As an organic macromolecule, humic acid (HA) has been extensively used as the protectant for bacteria applied in Cr(VI) microbial remediation. However, the effect of the structural properties of HA on the reduction rate of bacteria and the respective contribution of bacteria and HA to soil Cr(VI) management remained uncertain. In this paper, the structural differences between two kinds of humic acid (AL-HA and MA-HA) were explored by means of spectroscopy and electrochemical characterization, and the potential influence of MA-HA on Cr(VI) reduction rate and physiological characteristics of bacteria (Bacillus subtilis, SL-44) also were analyzed. The results showed that the phenolic groups and carboxyl on the surface of HA are firstly complex with Cr(VI) ions, and the fluorescent component with more п-п conjugate structure in HA is the most sensitive species. Compared with single bacteria, the application of SL-44 and MA-HA complex (SL-MA) not only enhanced the reduction of 100 mg/L Cr(VI) to 39.8 % within 72 h and formation rate of intermediate Cr(V), but also reduced the electrochemical impedance. Moreover, the addition of 300 mg/L MA-HA also relieved the Cr(VI) toxicity and decreased the accumulation of glutathione to 94.51 % in bacterial extracellular polymeric substance, furthermore down-regulated the gene expression related to amino acid metabolism and polyhydroxybutyric acid (PHB) hydrolysis in SL-44. Finally, the application of SL-MA also enhanced the stability of chromium in soil and decreased its phytoavailability to 86.09 %, which further reduced chromium enrichment in cabbage organs. These findings provide new insights into Cr(VI) removal, which is also critical for evaluating the application potential of HA for enhancing Cr(VI) bio-reduction.

Physiological and transcriptomic evidence of antioxidative system and ion transport in chromium detoxification in germinating seedlings of soybean

Chromium (Cr) toxicity impairs the productivity of crops and is a major threat to food security worldwide. However, the effect of Cr toxicity on seed germination and transcriptome of germinating seedlings of soybean crop has not been fully explored. In this study, two Cr-tolerant lines (J82, S125) and two Cr-sensitive ones (LD1, RL) were screened out of twenty-one soybean (Glycine max L.) genotypes based on seed germination rate, seed germinative energy, seed germination index, and growth of germinating seedlings under 50 mg L−1 Cr treatment. We found that Cr stress inhibits the growth of soybean seed germinating seedlings due to the Cr-induced overaccumulation of reactive oxygen species (ROS). Significantly different levels of element contents, antioxidant enzyme activities, malondialdehyde content were observed in the four soybean genotypes with contrasting Cr tolerance. Further, a total of 13,777 differentially expressed genes (DEGs) were identified in transcriptomic sequencing and 1298 DEGs in six gene modules were found highly correlated with the physiological traits by weighted correlation network analysis (WGCNA) analysis. The DEGs encoding antioxidant enzymes, transcription factors, and ion transporters are proposed to confer Cr tolerance in soybean germinating seedlings by reducing the uptake and translocation of Cr, decreasing the level of ROS, and keeping the osmotic balance in soybean germinating seedings. In conclusion, our study provided a molecular regulation network on soybean Cr tolerance at seed germinating stage and identified candidate genes for molecular breeding of low Cr accumulation soybean cultivars.

Retracted: Effects of Free Amino Acids, Metallothionein, and Chemical Forms of Heavy Metals on the Accumulation and Detoxification of Cadmium and Chromium in Chinese Goldthread (Coptis chinensis Franch.)

Retracted: Effects of Free Amino Acids, Metallothionein, and Chemical Forms of Heavy Metals on the Accumulation and Detoxification of Cadmium and Chromium in Chinese Goldthread (<i>Coptis chinensis</i> Franch.)

Pulsed-waveform electrocatalytic detoxification of hexavalent chromium promoted by pseudocapacitive effects

We report a pulsed-voltage method using a pseudocapacitive electrode to improve the efficiency of the electrochemical reaction for aqueous Cr(vi) detoxification.

Detoxification and Removal of Hexavalent Chromium in Aquatic Systems: Applications of Bioremediation

Chromium is a transition metal with a wide range of applications in leather tanning, textile, electroplating, stainless steel production, inorganic chemical production and wood preservation industries due to yellow colouration, corrosion resistance, higher melting-point and crystalline structure with raging of oxidation states from 0 to +6. Trivalent and hexavalent chromium are the most abundant forms of chromium discharged into the aquatic environment by industries. It has been reported that hexavalent chromium is highly toxic than trivalent chromium due to the higher solubility, mobility and tendency to accumulate in higher trophic levels, which, therefore, become bioavailable and causes carcinogenic, mutagenic and teratogenic effects on most microorganisms and animals, growth inhibition, morphological and physiological changes and yield reductions in plants. Therefore, it is essential to detoxify the above hazardous pollutants up to permissible limits, which local and international authorities have legislated concerning its threat towards biotic components. Hexavalent chromium detoxification is possible to achieve using three methods i.e. physical, chemical and biological methods. These remediation processes can eliminate highly toxic hexavalent chromium or transform it into a less toxic form of trivalent chromium, completely or partially by adsorption and reduction. Biological remediation is considered a cost-effective and ecofriendly method compared to physical and chemical remediation. Further, many biological agents have been identified as agents that can tolerate the hexavalent chromium toxicity up to certain higher levels depending on the internal and external environmental factors, indicating different metal tolerance mechanisms that are assumed to be applied in metal remediation aspects. According to the testimonies of novel bioremediation studies, some hexavalent chromium tolerant organisms such as plants, bacteria, unicellular and multicellular fungi and algae are promising eco-friendly alternatives in detoxification and hexavalent chromium removal perspective. This article reviews the bioremediation approaches available for hexavalent chromium detoxification and removal and highlights the strengths and weaknesses of current bioremediation methods.

Chromate Reduction by Allochromatium sp. Isolated from the Coastal Area of Visakhapatnam

A phototrophic purple bacterium Allochromatium sp. strain GSKRLMBKU–01 was used in this study for the reduction of hexavalent chromium. This phototrophic bacterium was isolated from samples collected from the coastal area of Visakhapatnam, India. Both the cells (free (FC) and alginate entrapped immobilized (IC)) are used for the reduction of chromate. Among them, chromate reduction was increased using immobilized cells. Immobilized cells entrapped in sodium alginate reduced the chromate up to 33 ± 3.0 μM on the 8th day of incubation by Allochromatium sp., incubated in presence of light (2000 lx) under the strictly anaerobic conditions, while a chromate reduction up to 26 ± 0.20 μM was recorded by FC of Allochromatium sp. Chromate reduction can be recorded even up to the 20th day by both FC and IC. An incubation period of 8 days was found to be optimum for its growth and chromate reduction. The maximum growth in terms of dry cell weight (DCW) of FC is recorded up to 1.7 ± 0.20 g.L-1 and IC is 2.0 ± 0.30 g.L-1. The growth was recorded even on complete chromate reduction. The final pH of the FC was recorded at pH 8.5 ± 0.10, while the final pH of 8.6 ± 0.20 was recorded for the IC of Allochromatium sp. in the growth medium. The obtained results were mentioned in terms of mean and standard deviation which are statistically significant at P ≤ 0.001 level. The detoxification of chromium in the large-scale systems by employing a purple phototrophic bacteria Allochromatium sp., is proposed.

Whole-genome sequencing of biofilm-forming and chromium-resistant mangrove fungus Aspergillus niger BSC-1

Filamentous fungus Aspergillus niger has gained significant industrial and ecological value due to its great potential in enzymatic activities. The present study reports the complete genome sequence of A. niger BSC-1 which was isolated from Indian Sundarban mangrove ecosystem. The study revealed that the genome of A. niger BSC-1 was 35.1 Mbp assembled in 40 scaffolds with 49.2% GC content. A total of 10,709 genes were reported out of which 10,535 genes were predicted for encoding the proteins. BUSCO assessment showed 98.6% of genome completeness indicating high quality genome sequencing. The genome sequencing of A. niger BSC-1 revealed the presence of rodA and exgA genes for initial adhesion to surface and Ags genes for matrix formation, during biofilm growth. OrthoVenn2 analysis revealed that A.niger BSC-1 shared 9552 gene clusters with the reference strain A. niger CBS554.65. Semi-quantitative RT-PCR analysis unveiled the role of Ags1 and P-type ATPase in fungal biofilm formation and chromium (Cr) resistance, respectively. During biofilm growth the expression of Ags1 significantly (P < 0.0001; two-way ANOVA followed by Sidak's multiple comparisons test) increased with respect to planktonic culture revealing the possible involvement of Ags1 in biofilm matrix formation. Expression of P-type ATPase gene was significantly upregulated (P < 0.0001; one-way ANOVA followed by Dunnett's multiple comparisons test) with the increasing chromium concentration in the fungal culture. Besides, several other genes encoding metalloprotease, copper and zinc binding proteins, and NADH-dependent oxidoreductase were also found in the genome of A. niger BSC-1. These proteins are also involved in heavy metal tolerance and nanofabrication indicating that this filamentous fungus A. niger BSC-1 could be potentially utilized for chromium detoxification through biofilm or nanobiremediation.

Effects of Free Amino Acids, Metallothionein, and Chemical Forms of Heavy Metals on the Accumulation and Detoxification of Cadmium and Chromium in Chinese Goldthread (Coptis chinensis Franch.)

Chinese goldthread (Coptis chinensis Franch.) is an important medicinal plant worldwide. However, its clinical safety is negatively impacted by high cadmium (Cd) and chromium (Cr) levels. Understanding the accumulation pattern and detoxification mechanism of heavy metals, such as Cd and Cr, is important for regulating their transportation and reducing their accumulation in plants. Free amino acids (FAAs), metallothioneins, and chemical forms of heavy metals are closely associated with heavy metal accumulation and detoxification mechanisms. In the present study, we evaluated the uptake of Cd and Cr in Chinese goldthread and characterized the changes in FAA levels, CcMT2, a metallothionein gene, expression under Cd and Cr stress, and Cr chemical forms in various tissues of Chinese goldthread. The majority of Cd and Cr was retained in the roots; this might be the tolerance strategy utilized by Chinese goldthread to protect the aboveground photosynthetic tissues. A chemical continuous extraction method was utilized to analyze the chemical forms of Cr, and the results suggested that Cr was primarily fixed by oxalate in all tissues, and after Cr treatment, Cr tended to combine with phosphate to form an insoluble complex that reduced the toxicity and bioavailability of Cr in Chinese goldthread. The accumulation of Cd and Cr was significantly positively correlated with valine, histidine, threonine, tyrosine, and serine levels and significantly negatively correlated with glutamic acid and alanine levels. The variation in proline levels under Cd stress was different than that under Cr stress. FAAs might affect the accumulation of and resistance to Cd and Cr through various detoxification strategies, such as chelation with heavy metals ions and conversion into the required products. Furthermore, CcMT2 was isolated for the first time and found to be dominantly expressed in leaves. CcMT2 was induced under Cd and Cr stress in all plant tissues, indicating its role in the accumulation of and tolerance to Cd and Cr.

Woodchip-sulfur based mixotrophic biotechnology for hexavalent chromium detoxification in the groundwater

This study investigated groundwater hexavalent chromium (Cr(VI)) decontamination by a biological permeable reactive barrier (bio-PRB), where a woodchip-elemental sulfur [S(0)] based mixotrophic process was established. 89.0 ± 0.27% of Cr(VI) was removed from the synthetic groundwater after 72 h at a concentration of 50 mg/L during the preliminary batch experiment. The impact of geochemical and hydrodynamic conditions Cr(VI) removal was investigated in the bio-PRB over 225 days. Although elevated Cr(VI) (i.e., 75 mg/L), addition of nitrate and short hydraulic retention time reduced the Cr(VI) removal, 87.2 ± 2.09% of Cr(VI) removal was accomplished. Characterization of the solids indicated that the soluble Cr(VI) was converted and immobilized as the insoluble trivalent chromium [Cr(III)]. 16S rRNA gene based sequencing results suggested that micromolecules produced by woodchip cellulose hydrolyzing- and sulfur oxidizing bacteria were further used by functional Cr(VI) removal bacteria (e.g., Geobacteraceae and Pseudomonas). The extracellular protein and humic-like substances in extracellular polymeric substances (EPS) can bind toxic Cr(VI) through carboxyl and hydroxyl groups, and reduce Cr(VI) in an enzymatic manner. The preliminary finding of this study provided a potential way to utilize agricultural waste for in-situ Cr(VI) contaminated-groundwater remediation.

Liquid exfoliated Bi2S3 nanosheets as photocatalysts for degradation of azo dyes and detoxification of hexavalent chromium

Layered materials represent a diverse source of two-dimensional crystals with exotic electronic properties and high specific surface areas essential for sensing, catalysis, and energy storage applications. Herein, bismuth sulfide (Bi2S3) crystals were ultrasonically exfoliated into nanosheets using N, N-dimethylformamide solvent. It was found that the as-prepared nanosheets with the atomic ratio of 2:3 for Bi (bismuth):S (sulphur) are rock-like structures consisting of multilayer sheets, orthorhombic phase, single-crystalline (d = 5.041 nm) in nature with 1.11 eV optical bandgap. The photocatalytic experiments showed excellent efficiency of up to 76.5 % in 240 min and 86.9 % in 50 min of visible light irradiation for methyl orange (MO) and Cr(VI), respectively. Both reactions follow a pseudo-kinetic first-order with kinetics constant (k) values of 0.0048 min−1 and 0.023 min−1 in terms of MO and Cr(VI), respectively. The probable mechanism strongly supports that Bi2S3 nanosheets are effective photocatalysts for water decontamination.