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ABSTRACT
Consumption of water contaminated with dyes and phenolic compounds is detrimental to human and animal wellbeing even at permissible limits. Therefore, their decontamination from water is important for the safety of consumers. Conventional water treatment techniques such as ozonation, ion exchange among others are expensive and ineffective. Adsorption as an emerging technique has gained research interest because of its ease in design, environmentally friendly and availability of materials as adsorbents in large quantities. The application of various adsorbents have extensively been reported for decontamination of dyes and phenolic compounds in wastewater such as 4-chlorophenol, Metanil Yellow (MY) dye, Phenol, Methyl green dye, Bromothymol Blue dye, Crystal violet, Methylene blue and Direct Blue 71. It has also been reported that adsorption by column continuous processes are more efficient than batch as it can be used continuously under high effluent flow rates in many pollution control processes in an industrial set up. The fixed bed column adsorption data is analyzed at different column conditions of bed height, pH, particle size, concentration and flow rate using different kinetic models such as Bohart-Adams, Thomas, Yoon-Nelson, Clark, Bed depth service time and Wolborska models amongst others to determine the column performance. The present paper involves a mini review of dynamics of fixed-bed column studies for removal of selected dyes and phenolics from a synthetic media.
Keywords: Fixed bed column, Phenols, dyes, Breakthrough curves, Bed capacity.
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1.INTRODUCTION
Water is an essential resource for sustaining life to humans, plants and animals1,2. Streams, rivers and wells are source of drinking water for many rural folks3. However, these water sources are polluted due to rapid industrial advancements in our societies4,5,6. This has resulted to a continued discharge of toxic organic and inorganic pollutants such as heavy metal ions, dyes, phosphate compounds, phenolics amongst others into these water sources7.
One of these organic pollutants of environmental concern are dyes and phenolic compounds8,9. Phenols are discharged to water bodies from industrial effluents of pharmaceuticals, petroleum refineries, pesticide manufacturing, paint production, paper and pulp industries amongst others10,11. A phenolic compound contain hydroxyl group(s) which are bonded directly to a benzene ring12. These hydroxyl groups dissociate easily in water forming stable phenolate ions13. Their presence in water bodies is toxic and...