Application of response surface methodology in physicochemical removal of dyes from wastewater: A critical review

Response surface methodology (RSM) is a powerful tool in designing the experiments and optimizing different environmental processes. However, when it comes to wastewater treatment and specifically dye-containing wastewater, two questions arise; “Is RSM being used correctly?” and “Are all capabilities of RSM being exploited properly?”. The current review paper aims to answer these questions by scrutinizing different physicochemical processes that utilized RSM in dye removal. The literature that applied RSM to adsorption, advanced oxidation processes, coagulation/flocculation and electrocoagulation processes were critically reviewed in this paper. The common errors in applying RSM to physicochemical removal of dyes are identified and some suggestions are made for future studies. [Display omitted] •Step-by-step procedure of applying RSM to physicochemical dye removal is presented.•12 different physicochemical processes that used RSM in dye removal are investigated.•92 studies that utilized RSM in physicochemical removal of dyes are analyzed.•Common errors of applying RSM to physicochemical treatment of dyes are identified.•Results are critically discussed and useful suggestions are made for future studies.