Design of solvent mixtures for removal of phenol from wastewater using a non-linear programming model with a multi-start method

Abstract

The optimization-based design of solvent mixtures used for phenolic wastewater treatment was investigated in this work. A nonlinear programming （NLP） model was formulated based on the concepts of computer-aid molecule design (Computer-Aided Molecular Design, CAMD) to select solvent mixtures with the best extraction performance considering the constraints of extraction process and the environmental impact. Due to the complexity of the NLP model, multi-start method was adopted to solve this problem in order to get near global optimal solution. The results of the calculations suggested that the optimal mixture consisted of 70.1% n-octanol and 29.9% 2-octanone (molar fraction).The 119 sets of experimental results showed that the extraction ability of the optimal solvent mixture identified by CAMD technique was among the top 6 sets compared to the experiment results. The results suggested that the developed NLP model could be able to screen the optimal solvent mixture in phenolic wastewater treatment.