A review on heavy metal pollution, toxicity and remedial measures: Current trends and future perspectives

Recent advances for dyes removal using novel adsorbents: A review

There are number of water purification techniques but the adsorption is one of the most simplest, effective and economical method for wastewater purification. In this article a large number of solid adsorbents such as Natural adsorbents, Agricultural Wastes, Industrial wastes, Biomass, Nanoadsorbents: Carbon based nanomaterials, Nobel metal based nanomaterials, Metal oxide based nanomaterials, Spinel ferrite based nanomaterials, Nanocomposites, Dendritic polymers; Geopolymer cement have been discussed for the removal of different pollutants from waste water. Removal of Fluoride, Phosphate, Nitrate and Radionuclides from wastewater has also been reviewed in this article. Adsorption isotherm models, kinetic models, thermodynamic parameters and adsorption mechanism have also been discussed. The present article lists different type of adsorbents and reviews state-of-the-art of the removal of different pollutants from water. The efforts have been made to discuss the sources of contamination and toxicities of pollutants. Adsorption mechanisms responsible for pollutants removal by different adsorbents have been reviewed. Attempts have also been made to point out the advantages and drawbacks of adsorbents and the future research needs in the area of water purification by adsorbents.

Water purification by using Adsorbents: A Review

Presence of toxic and recalcitrant heavy metal ions in industrial effluents is a major environmental concern. These fatal metal ions are not only hazardous in exceeding concentrations but due to the property of biomagnification it is urgent to look for the plausible solutions. This review article is an attempt to gather the research findings attempted in yester years for the removal of such metals from aqueous solutions by using waste materials from industries, such as blast furnace sludge, slag and flue dust, fly ash, black liquor lignin, and red mud. Studies have been complied keeping various efficiency influencing parameters such as optimum dose, contact time, initial concentration of metal ions, and many more in consideration. This article also tries to summarize the various problems and shortcoming of the work carried so far and attempts to explore the feasible suggestions.

A review on potential usage of industrial waste materials for binding heavy metal ions from aqueous solutions

Metallurgical process for valuable elements recovery from red mud—A review

Adsorption studies of arsenic(III) removal from water by zirconium polyacrylamide hybrid material (ZrPACM-43)

In this work, batch adsorption study was conducted to investigate the removal efficiency of Pb(II) from the aqueous solutions by using HCl activated red mud (ARM). Adsorption experiments were conducted as a function of adsorbent dose, equilibrium pH, contact time, initial lead concentration, kinetics and Langmuir isotherms. The characterization and mechanisms involved in adsorption of lead ions on ARM were studied by using instrumental technique like XRD, FTIR, SEM/EDX, TG-DSC and chemical methods. The percentage removal was found to increase gradually with decrease of pH and maximum removal was achieved at pH 4. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The adsorption data were fitted to linearly transformed Langmuir isotherm with R 2 (correlation coefficient) > 0.99. The results indicate that ARM can be used as an effective and low cost adsorbent for the treatment of wastewaters contaminated with Pb(II) ions.

Removal of Pb(II) from aqueous solution by acid activated red mud

Investigating the selectivity and interference behavior for detoxification of Cr(VI) using lanthanum phosphate polyaniline nanocomposite via adsorption-reduction mechanism.

Response surface methodology (RSM) was applied to examine the removal of hazardous safranin-O dye from aqueous solution by CO2 neutralized activated red mud. A 24 full factorial central composite design (CCD) was used to evaluate the effects of adsorption parameters such as, adsorbent dose (X1), temperature (X2), solution pH (X3) and initial safranin-O concentration (X4) on percentage removal of safranin-O dye from aqueous solution. Analysis of variance (ANOVA) exhibit a high R2 value of 0.9655, indicating second-order regression model excellently evaluate the experimental data. The interaction effects of the main factor and optimum condition of the process were determined from contour and response surface plots, respectively. In addition, the isotherm study revealed that, the adsorption data were best fitted to Langmuir model with high correlation value of 0.994 and adsorption capacity of 9.7680 mg g−1. The optimum operating condition for adsorption of safranin-O dye were obtained as adsorbent dose (0.62 g), temperature (29.06 °C), pH (8.3) and initial safranin-O concentration (37.3 mg L−1). At the optimum condition, the adsorption of safranin-O from aqueous solution was found to be 94.5 ± 0.1%.

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Correction: Adsorption of safranin-O dye on CO2 neutralized activated red mud waste: process modelling, analysis and optimization using statistical design

The fluoride ion removal from aqueous solution using synthesized Mg-Cr-Cl layered double hydroxide has been reported. Mg-Cr-Cl was characterized by X-ray powder diffraction, Fourier-transform infrared, thermo-gravimetric analysis, differential thermal analysis, and scanning electron microscope. Adsorption experiments were carried out in batch mode as a function of adsorption dosages, contact time, pH, and initial fluoride concentration to get optimum adsorption capacity. The adsorption kinetic study showed that the adsorption process followed first order kinetics. The fluoride removal was 88.5% and 77.4% at pH 7 with an adsorbent dose of 0.6 g/100 mL solution and initial fluoride concentration of 10 mg/L and 100 mg/L, respectively. The equilibrium was established at 40 min. Adsorption experiment data were fitted well with Langmuir isotherm with R2 = 0.9924. Thermodynamic constants were also measured and concluded that the adsorption process was spontaneous and endothermic in nature. The removal percentage decreased slowly with increasing pH. This process is suitable for industrial effluents. The regeneration of the material is not possible.

Manoj Kumar Sahu

Papers

Adsorption studies of arsenic(III) removal from water by zirconium polyacrylamide hybrid material (ZrPACM-43)

Removal of Pb(II) from aqueous solution by acid activated red mud

Investigating the selectivity and interference behavior for detoxification of Cr(VI) using lanthanum phosphate polyaniline nanocomposite via adsorption-reduction mechanism.

Correction: Adsorption of safranin-O dye on CO2 neutralized activated red mud waste: process modelling, analysis and optimization using statistical design

Removal efficiency of fluoride by novel Mg-Cr-Cl layered double hydroxide by batch process from water.