Investigation on removal of malachite green using EM based compost as adsorbent T. Bhagavathi Pushpa a , J. Vijayaraghavan a , S.J. Sardhar Basha b , V. Sekaran c , K. Vijayaraghavan d , J. Jegan a,n a Department of Civil Engineering, University College of Engineering, Ramanathapuram, TN, India b Department of Chemistry, University College of Engineering, Ramanathapuram, TN, India c Department of Civil Engineering, Paavai Engineering College, Namakkal, TN, India d Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, India article info Article history: Received 10 January 2015 Received in revised form 21 April 2015 Accepted 23 April 2015 Keywords: Malachite green Dye Compost Effective Microorganisms Isotherms Biosorption abstract The discarded materials from different sources can be utilized as effective materials in wastewater re- mediation. This proposed study was aimed mainly to investigate the possibility of Effective Micro- organisms based compost (EM KC ), which is derived from the kitchen solid waste, as a non-conventional low cost adsorbent for the removal of malachite green from aqueous solution. Batch experiments were carried out to evaluate the optimum operating parameters like pH (2–9), initial dye concentration (50– 1000 mg/L), adsorbent particle size (0.6–2.36 mm) and adsorbent dosage (2–12 g/L). EM KC recorded maximum uptake of 136.6 mg/g of MG at pH 8, initial dye concentration 1000 mg/L, adsorbent particle size 1.18 mm and adsorbent dosage 4 g/L. Two and three parameter adsorption models were employed to describe experimental biosorption isotherm data. The results revealed that the Sips model resulted in better fit than other models. The pseudo-first and -second order models were applied to describe kinetic data, of which the pseudo-second order described experimental data better with high correlation coefficient. This investigation suggested that EM KC could be an effective and low cost material for the removal of malachite green dye from aqueous solution. & 2015 Elsevier Inc. All rights reserved. 1. Introduction The textile industry releases the waste water into the natural streams and the environment which may contain more con- taminants such as acids, bases, dissolved solids, toxic organic and inorganic compounds and colors. These toxic contaminants cause major hazards to the environment and living entity. Dyes and pigments present in wastewater have high visibility. Thus even minor release into the environment may cause the appearance of color which attracts the critical attention of public and local au- thorities. Also, usage of this stained water creates many diseases to the human being and animals. There are more than 100,000 commercial dyes exist and more than 7  10 5 t per year produced annually (McMullan et al., 2001; Pearce et al., 2003). A synthetic dye in wastewater can be removed by traditional methods like coagulation, filtration, electro floatation etc. However these methods are usually inefficient, costly and not adaptable to a wide range of dye wastewaters. (Ghoreishi and Haghighi, 2003). Malachite green (MG) is a basic (cationic) dye, which is water- soluble mainly applied to acrylic fibers, wool and silk. On the other hand, MG discharged into receiving water bodies, even at low concentrations, will affect the aquatic life and cause detrimental effects in liver, gill, kidney, intestine and gonads. In humans, it may cause irritation to the gastrointestinal tract upon ingestion. Also when contacted with skin causes irritation, redness and pain (Daneshvar et al., 2007). Biological treatment is often the most economical alternatives to eradicate the dye in an industrial wastewater when compared with other physical and chemical processes. Biodegradation methods such as fungal decolorization, microbial degradation, adsorption by (living or dead) microbial biomass and bior- emediation systems are commonly applied to the treatment of industrial effluents, because many microorganisms such as bac- teria, yeasts, algae and fungi are able to accumulate and degrade different pollutants (McMullan et al., 2001; Fu and Viraraghavan, 2001). Biosorption is a well-established technique for the removal of textile dyes (Chowdhury et al., 2011) from aqueous solution. A variety of materials are used as adsorbents for dyes and this in- clude activated carbon, starch xanthate, alumina, low-grade Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety http://dx.doi.org/10.1016/j.ecoenv.2015.04.033 0147-6513/& 2015 Elsevier Inc. All rights reserved. n Corresponding author. E-mail address: drjeganjoe@gmail.com (J. Jegan). Ecotoxicology and Environmental Safety 118 (2015) 177–182