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A novel composite film with efficient removal of anionic dye (Congo red) was developed using chitosan and dialdehyde microfibrillated cellulose nano fibrils. Microfibrillated cellulose with three dimensional network structure was prepared from microcrystalline cellulose by high-pressure homogenization. Then it was surface modified by periodate to prepare dialdehyde microfibrillated cellulose (DAMFC). DAMFC/chitosan composite films were prepared by solvent-casting. During the compounding of DAMFC with chitosan, a Schiff base was formed through the reaction between the aldehyde groups of DAMFC and amino groups of chitosan. A giant network structure was therefore formed. The addition of DAMFC resulted in remarkably increased adsorption capacity of the chitosan material as well as drastically improved stability in dye solution. The adsorption performance was investigated with respect to pH, temperature, contact time, and the initial dye concentration. The possible adsorption mechanism was proposed. Various isotherm models have been used to fit the data, and kinetic parameters were evaluated., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Field treatment of textile industry effluent was carried out in constructed drenches (91.4m×1.2m×0.6m; 65.8m 3 ) planted independently with Typha angustifolia, Paspalum scrobiculatum and their co-plantation (consortium-TP). The in situ treatment of effluent by T. angustifolia, P. scrobiculatum and consortium-TP was found to decrease ADMI color value by 62, 59 and 76%, COD by 65, 63 and 70%, BOD by 68, 63 and 75%, TDS by 45, 39 and 57%, and TSS by 35, 31 and 47%, respectively within 96h. Heavy metals such as arsenic, cadmium, chromium and lead were also removed up to 28-77% after phytoremediation. T. angustifolia and P. scrobiculatum showed removal of Congo Red (100mg/L) up to 80 and 73%, respectively within 48h while consortium-TP achieved 94% decolorization. Root tissues of T. angustifolia and P. scrobiculatum revealed inductions in the activities of oxido-reductive enzymes such as lignin peroxidase (193 and 32%), veratryl alcohol oxidase (823 and 460%), laccase (492 and 182%) and azo reductase (248 and 83%), respectively during decolorization of Congo Red. Anatomical studies of roots, FTIR, HPLC, UV-vis Spectroscopy and GC-MS analysis verified the phytotransformation. Phytotoxicity studies confirmed reduced toxicity of the metabolites of Congo Red., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The present study deals with the decolorization and detoxification of Congo red (CR) by a novel marine bacterium Dietzia sp. (DTS26) isolated from Divar Island, Goa, India. The maximum decolorization of 94.5% (100 mg L(-1)) was observed under static condition within 30 h at pH 8 and temperature 32±2°C. Bacterially treated samples could enhance the light intensity by 38% and the primary production levels 5 times higher than the untreated. The strain was also able to reduce COD by 86.4% within 30 h at 100 mg L(-1) of CR dye. The degraded metabolites of CR dye were analyzed by FTIR, HPLC, GC-MS and the end product closely matches with 4-amino-3-naphthol-1-sulfonate which is comparatively less toxic than CR. Bioassay experiments conducted in treated samples for Artemia franciscana showed better survival rates (after 72 h) at higher concentration of CR (500 mg L(-1)). This work suggests the potential application of DTS26 in bioremediation of dye wastes and its safe disposal into coastal environment., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Extensive use of synthetic dyes in many industrial applications releases large volumes of wastewater. Wastewaters from dying industries are considered hazardous and require careful treatment prior to discharge into receiving water bodies. Dyes can affect photosynthetic activities of aquatic flora and decrease dissolved oxygen in water. The aim of this study was to evaluate the effect of Congo red on growth and metabolic activity of Chlorella vulgaris after 96h exposure. Exposure of the microalga to Congo red reduced growth rate, photosynthesis and respiration. Analysis of chlorophyll a fluorescence emission showed that the donor side of photosystem II was affected at high concentrations of Congo red. The quantum yield for electron transport (φEo), the electron transport rate (ETR) and the performance index (PI) also decreased. The reduction in the ability to absorb and use the quantum energy increased non-photochemical (NPQ) mechanisms for thermal dissipation. Overall, Congo red affects growth and metabolic activity in photosynthetic organisms in aquatic environments., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Congo red, an azo dye derived from benzidine, and 2-azoxyfluorene, a derivative of 2-aminofluorene, were reduced during overnight incubation with a suspension of rat intestinal bacteria. High performance liquid chromatography and ultraviolet spectral analysis verified the presence of benzidine in extracts of the Congo red incubations and 2-aminofluorene in extracts of the 2-azoxyfluorene incubations. Extracts of the Congo red incubations were mutagenic toward Salmonella typhimurium TA1538 in the presence of a post-mitochondrial activating system, but Congo red was not mutagenic without this reductive pretreatment. Thus, the utility of the Ames test in screening for potential mutagens may be expanded by a reductive pretreatment utilizing cecal bacteria.

The effects of the sublethal concentration (0.012%) of Congo Red on Heteropneustes fossilis were studied after 30 days exposure. The RBC count haemoglobin (Hb)% and PCV decreased significantly. The total WBC count, MCV, MCH, and MCHC showed a significant increase. Serum calcium, serum cholesterol and blood urea nitrogen (BUN) were significantly elevated, whereas serum phosphorus was significantly reduced. The activities of serum alkaline phosphatase (AlPase), acid phosphatase (AcPase). RNase, GOT, GPT and amylase were also significantly elevated. The possible reasons for these changes are discussed.