Application of low-cost adsorbents for dye removal – A review

As the environment preservation gradually becomes a matter of major social concern and more strict legislation is being imposed on effluent discharge, more effective processes are required to deal with non-readily biodegradable and toxic pollutants. Synthetic organic dyes in industrial effluents cannot be destroyed in conventional wastewater treatment and consequently, an urgent challenge is the development of new environmentally benign technologies able to mineralize completely these non-biodegradable compounds. This review aims to increase the knowledge on the electrochemical methods used at lab and pilot plant scale to decontaminate synthetic and real effluents containing dyes, considering the period from 2009 to 2013, as an update of our previous review up to 2008. Fundamentals and main applications of electrochemical advanced oxidation processes and the other electrochemical approaches are described. Typical methods such as electrocoagulation, electrochemical reduction, electrochemical oxidation and indirect electro-oxidation with active chlorine species are discussed. Recent advances on electrocatalysis related to the nature of anode material to generate strong heterogeneous OH as mediated oxidant of dyes in electrochemical oxidation are extensively examined. The fast destruction of dyestuffs mediated with electrogenerated active chlorine is analyzed. Electro-Fenton and photo-assisted electrochemical methods like photoelectrocatalysis and photoelectro-Fenton, which destroy dyes by heterogeneous OH and/or homogeneous OH produced in the solution bulk, are described. Current advantages of the exposition of effluents to sunlight in the emerging photo-assisted procedures of solar photoelectrocatalysis and solar photoelectro-Fenton are detailed. The characteristics of novel combined methods involving photocatalysis, adsorption, nanofiltration, microwaves and ultrasounds among others and the use of microbial fuel cells are finally discussed.

Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods. An updated review

http://textilamir.persiangig.com/document/3.pdf

Cationic and anionic dye adsorption by agricultural solid wastes: A comprehensive review

Dye effluents released from numerous dye-utilizing industries are harmful towards the environment and living things. Consequently, existence of dye effluent in environmental water bodies is becoming a growing concern to environmentalists and civilians. A long term sustainable and efficient dye effluent treatment method should be established to eliminate this issue. Dye wastewater should be treated first before release to minimize its negative impacts towards the environment and living things. However, due to lack of information on efficient dye removal methods, it is difficult to decide on a single technique that resolves the prevailing dye effluent issue. Therefore, this paper reviews existing research papers on various biological, chemical and physical dye removal methods to find its efficiency through percentage of dye removal. Although there are numerous existing tried and tested methods to accomplish dye removal, most of them have a common disadvantage which is the generation of secondary pollution to the environment. This paper highlights enzyme degradation (biological) and adsorption (physical) dye removal as these are known as one of the most efficient dye removal techniques these days. This paper also suggests the usage of a combined adsorbent as it is envisioned that this technique has better efficiency and is able to remove dyes at a faster rate.

Efficiency of various recent wastewater dye removal methods: A review

https://cyberleninka.org/article/n/638974.pdf

Characteristics and adsorption capacities of low-cost sorbents for wastewater treatment: A review

Adsorption of malachite green on groundnut shell waste based powdered activated carbon

Physico-chemical and surface characterization of activated carbon prepared from groundnut shell, an abundantly available carbonaceous solid waste from oil processing mills in India, by chemical activation were carried out. The effect of various activation conditions viz. time, temperature and ZnCl2 / char ratio on the % yield of product and adsorption efficiency in terms of iodine number was studied. Changes in surface morphology of char before and after activation were examined by scanning electron microscopy which showed well developed pore structure in activated carbon demonstrating corrosive effect of ZnCl2. Surface modifications through chemical changes were studied by FTIR spectroscopy which showed considerable development and increase of surface functional groups in activated carbon as compared to char. The developed adsorbent was utilized for the removal of acid dye from aqueous solution and its adsorption capacity was found to be 55.5 mg/g of the adsorbent for 100 ppm initial concentration of dye solution. Adsorption parameters for Freundlich and Langmuir isotherm models were examined for dye adsorption and for the validity of models to analyze the equilibrium data, it was found that Freundlich model fitted better than Langmuir. The results indicate that Groundnut Shell based Powdered Activated Carbon (GSPAC) could be employed as low-cost alternative adsorbent to commercial activated carbon in the wastewater treatment for removal of acid dyes.

http://nopr.niscair.res.in/bitstream/123456789/7048/1/IJCT%2013%284%29%20319-328.pdf

D. S. Ramteke

Papers

Adsorption of malachite green on groundnut shell waste based powdered activated carbon

Physico-chemical and surface characterization of adsorbent prepared from groundnut shell by ZnCl2 activation and its ability to adsorb colour