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Green Adsorbents for Wastewaters: A Critical Review
Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-541 24, Greece
Department of Petroleum and Natural Gas Technology, Technological Educational Institute of Kavala, Kavala GR-654 04, Greece
* Author to whom correspondence should be addressed.
Received: 4 November 2013; in revised form: 26 December 2013 / Accepted: 31 December 2013 / Published: 13 January 2014
Abstract: One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i) dyes; (ii) heavy metals; (iii) phenols; (iv) pesticides and (v) pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called “green adsorption”. Under this term, it is meant the low-cost materials originated from: (i) agricultural sources and by-products (fruits, vegetables, foods); (ii) agricultural residues and wastes; (iii) low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources). These “green adsorbents” are expected to be inferior (regarding their adsorption capacity) to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc.), but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful) topics such as: (i) adsorption capacity; (ii) kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes) and (iii) critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry) with economic analysis and perspectives of the use of green adsorbents.
Keywords: green adsorbents; wastewaters; agricultural wastes; techno-economical analysis; low-cost materials; dyes; heavy metals; phenols; pesticides
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Kyzas, G.Z.; Kostoglou, M. Green Adsorbents for Wastewaters: A Critical Review. Materials 2014, 7, 333-364.
Kyzas GZ, Kostoglou M. Green Adsorbents for Wastewaters: A Critical Review. Materials. 2014; 7(1):333-364.
Kyzas, George Z.; Kostoglou, Margaritis. 2014. "Green Adsorbents for Wastewaters: A Critical Review." Materials 7, no. 1: 333-364.