Non-conventional low-cost adsorbents for dye removal: A review

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

Dye and its removal from aqueous solution by adsorption: A review

Adsorption of methylene blue on low-cost adsorbents: A review

The adsorption kinetics of the cationic dye, methylene blue, onto clay.

In this study, adsorption of methylene blue onto clay was investigated. The effect of adsorption time and temperature on the adsorption process was studied. To reveal the adsorptive characteristics of the clay studied, porosity and BET surface area measurements were made. It was observed that the adsorption capacity decreases with increasing temperature, and adsorption equilibrium was attained within 1 h. It was found that the data fit well to Langmuir, Halsey, Henderson, and Harkins-Jura models but experimental data deviate significantly from BET and Freundlich models at especially high concentrations. Furthermore, isosteric adsorption enthalpy and entropy are calculated as -7.99 kJ mol(-1) and 25.41 JK(-1)mol(-1), respectively.

Determination of adsorptive properties of clay/water system: methylene blue sorption.

Electrocoagulation of some reactive dyes: a statistical investigation of some electrochemical variables

The removal of lignin and phenol from paper mill effluents by electrocoagulation.

Production of granular activated carbon from waste Rosa canina sp. seeds and its adsorption characteristics for dye.

Çetin Doğar

Papers

The adsorption kinetics of the cationic dye, methylene blue, onto clay.

Determination of adsorptive properties of clay/water system: methylene blue sorption.

Electrocoagulation of some reactive dyes: a statistical investigation of some electrochemical variables

The removal of lignin and phenol from paper mill effluents by electrocoagulation.

Production of granular activated carbon from waste Rosa canina sp. seeds and its adsorption characteristics for dye.