The role of catalyst in the adsorption of dye: Homogeneous catalyst, heterogeneous catalyst, and advanced catalytic activated carbon, critical review

Catalysts are very prominent in modifying activated carbon and other materials used in water purification such as removing contaminants in industrial effluent. A catalyst is described as a substance that when incorporated into an absorbent or base material enhances the properties and at the same time remains unconsumed in the process. Hence, this paper focused on the role of catalyst in dye adsorption techniques designed to remove dye pollutants from its effluent. The adsorption method of dyes particularly on activated carbon (AC) or the composite AC type is inexpensive, however, in terms of its productivity combined with the solid supports it is one of the easiest and most efficient approaches for eliminating dyes from effluent water. However, eliminating the remains after treatment procedures becomes a huge challenge. Therefore, advanced oxidation processes (AOPs) are extensively recognized as successful developments for treating dye-adulterated water owing to its absolute degradation of organic compounds to form water and carbon (IV)oxide. Amongst numerous AOPs, advanced heterogeneous catalysis, advanced catalytic activated carbon, advanced photocatalytic adsorbent, advanced catalytic oxidation process, and composite of the catalyst with biomass for dye removal were investigated and discussed in this review work. They were found to be spellbound with significant attention for their cost efficiency, and ecological friendliness. Studies of the affinity of each material in the hybrid system could be carried out to enable ease of modification for new contaminants. The effect of the material on the degradation rate could be studied also.