Treatment Of Dye Contaminated Water Research Articles

Fabrication of bio-polymer-based hydrogel for methylene blue remediation: Kinetics, mechanisms, and environmental implications

ABSTRACT Due to the presence of highly persistent and non-biodegradable dyes that are capable of causing harm to people, plants, animals, and the environment, the treatment of dye-contaminated water tends to be highly challenging. In the current work, polyacrylic acid and bio-polymer-based hydrogels of hydroxyl ethyl cellulose (HEC) were prepared through the free radical polymerization method and were used as adsorbents for the adsorption of methylene blue (MB). To estimate the nature and mechanism of adsorption, kinetics, and isotherm models were adopted. Pseudo-second-order kinetic model was followed by the sorption of MB. Results demonstrated that with an increase in concentration of dye dosage, adsorption increases linearly. Freundlich isotherm model was followed for the sorption of MB onto polyacrylic acid and bio-polymer-based hydrogels. Thermodynamic study of the adsorption process reveals that the adsorption process was spontaneous and endothermic as inferred from Gibbs free energy and enthalpy values of 33.08 kJ/mol and 3.83 kJ/mol at 303K, respectively. Recycling performance was tested and inferred that bio-polymer-based hydrogel having 0.6 gm. Hydroxyethyl cellulose decreases its adsorption efficiency equivalent to 5% after consecutive five cycles. The bio-polymer-based hydrogels will be used as an effective adsorbent for removing cationic dyes from wastewater on an industrial scale.

Optimization of Biosorption Conditions for Surfactant Induced Decolorization by Anaerobic Sludge Granules

AbstractThe sorption of Remazol Black B (RBB) by dried anaerobic sludge granules (ASG) was examined in this study. The biosorption process was monitored based on the statistical optimization data of the batch reactor studies. In the factorial tests, 36 different tests were established by considering the variables such as temperature (25°C, 50°C), pH (1, 3, 5), dye concentration (100, 150, 200 mg/L) and cationic surfactant concentration (0, 0.5 mM). Also, it was intended to investigate the effect of cationic surfactant dodecyl trimethylammonium bromide (DTAB) on decolorization of the anionic dye RBB by ASG. The sorption isotherms and kinetics were determined for RBB removal. The biosorption of RBB was fitted with Langmuir isotherm and pseudo-second-order kinetic models. The oppositely charged dye and surfactant molecules interacted electrostatically. These electrostatic interactions improved the dye biosorption properties of ASG. Our results indicate that a surfactant can be used as an inducer in the treatment of dye-contaminated water. This is the first paper combining factorial experiment design and surfactant-accelerated decolorization to achieve more effective biosorption conditions.

Kinetics and isotherm analysis of Tropaeoline 000 adsorption onto unsaturated polyester resin (UPR): a non-carbon adsorbent

The presence of dyes in water is undesirable due to the toxicological impact of their entrance into the food chain. Owing to the recalcitrant nature of dyes to biological oxidation, a tertiary treatment like adsorption is required. In the present study, unsaturated polyester resin (UPR) has been used as a sorbent in the treatment of dye-contaminated water. Different concentrations of Tropaeoline 000 containing water were treated with UPR. The preliminary investigations were carried out by batch adsorption to examine the effects of pH, adsorbate concentration, adsorbent dosage, contact time, and temperature. A plausible mechanism for the ongoing adsorption process and thermodynamic parameters have also been obtained from Langmuir and Freundlich adsorption isotherm models. Thermodynamic parameter showed that the sorption process of Tropaeoline 000 onto activated carbon (AC) and UPR were feasible, spontaneous, and endothermic under studied conditions. The estimated values for (ΔG) are -10.48 × 10(3) and -6.098 × 10(3) kJ mol(-1) over AC and UPR at 303 K (30 °C), indicating towards a spontaneous process. The adsorption process followed pseudo-first-order model. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order kinetic models. The values of % removal and k (ad) for dye systems were calculated at different temperatures (303-323 K). The mechanism of the adsorption process was determined from the intraparticle diffusion model.