A comprehensive review on adsorption of Reactive Red 120 dye using various adsorbents

The textile industry has a crucial role in our economy. This industry generates wastewater that contains dangerous dyes as well as pigments, suspended and dissolved solids, and heavy metals that are untreated or used directly for irrigation purposes, released into soil and water receptors, thus negatively affecting the environment. Several dyes have an impact on the human health and aquatic biota due to their toxic and even carcinogenic nature. One of the dyes widely utilized in the textile industry, Reactive Red 120 (RR120), poses a risk to the aquatic system because of its low biodegradability. There are many methods to decontaminate dye-containing wastewater such as physical, chemical, and biological processes. Adsorption is an attractive method owing to its simplicity, easy operation, and low cost. This review article explores the elimination of RR120 dye by different adsorbents. Special emphasis is given to the various adsorption parameters that affect the adsorption process, the adsorption mechanism, regeneration, and thermodynamic studies. The results demonstrated that the RR120 dye could be removed from wastewater by a wide range of different adsorbents, including chitosan, clay, carbonaceous materials, and biomass wastes, with a maximum capacity varying from 1.45 to 482.2 mg/g. The pseudo-second-order kinetic equations and Langmuir isotherm gave the best fit to the adsorption data. Future work will focus on analyzing the costs associated with the preparation and application of the various adsorbents to remove the RR120 dye and investigating their potential in column studies and also in more realistic conditions such as using real wastewater.