This review discusses the methods for the removal of dyes from the wastewater effluents. Wastewater effluents contain synthetic dyes which cause a potential hazard to the environment hence these dyes need to remove from the water bodies. The various dye removal techniques are classified into Chemical, Physical, and Biological methods. Physical methods includes adsorption, ion exchange, and filtration/coagulation methods etc. while chemical methods includes ozonisation, Fenton reagent, photo catalytic reactions and biological methods include aerobic degradation, anaerobic degradation, biosorption etc. Adsorption found to be very effective and cheap method among the all available dye removal methods. Dyes from the industrial waste water effluents are effectively separated by using adsorbent such as activated carbon however its cost restricts the use in large scale applications. Experimental studies proved that the effective removal of dyes is obtained using several cheaply available non-conventional adsorbents also. Therefore, studies related to searching for efficient and low cost adsorbents derived from existing resources are gaining importance for the removal of dyes.

Textile industry is one of the fast growing industries and is consuming and polluting large volumes of water. Four isotherms i.e. Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich were studied to evaluate the adsorbent efficiency of Vigna Trilobata pod in removal of dye from aqueous solution. Methylene blue was taken as the model pollutant in this study. Among all the above mentioned isotherms Freundlich adsorption isotherm model was found to be fitted well with the experimental data with high regression coefficient, R 2 ≥99. Isotherm studies proved that Vigna Trilobata pod is very efficient for the removal of Methylene blue.

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In the present study, an efficiently, economically, and eco-friendly green carbon biosorbent derived from the plant bio waste, Acacia Arabica fruit, was used to treat aqueous solutions containing a basic dye, Methylene Blue (MB). The effect of various process parameters such as temperature, pH of solution, initial dye concentration and biosorbent dosage on dye removal was studied by using experimental runs designed by Central Composite Design. The optimization studies were carried out by changing the temperature in the range of 293-323 K, pH between (6-11), initial dye concentration between (25-150 mg/l), and adsorbent dosage between (0.05-0.25g). Regression and ANOVA data was analysed to know the interaction effect of dye on the biosorbent. A hybrid RSM-GA based technique was successfully developed to model, simulate, and optimize the biosorption process. The performance of the RSM-GA method was found to be very impressive. Results proved that the prepared green carbon biosorbent was highly efficient and economical for Methylene Blue removal from aqueous solutions.