Remediation of bis(2-Ethylhexyl) Phthalate and Phenol, 4,4′-(1-Methylethylidene)bis—in Landfill Leachate Using Biopolymer

Abstract

Persistent organic pollutants (POPs) are global contaminants that have significant toxic effects and possess carcinogenicity, mutagenicity, neurotoxicity, immunotoxicity and endocrine disruption characteristics. This study aimed to investigate the effectiveness of Locust Bean Gum (LBG) in eliminating POPs such as phenol, 4,4′-(1-methylethylidene)bis-(bisphenol A) and bis(2-ethylhexyl) phthalate (DEHP) from landfill leachate and compared it with the removal efficiency by using alum. Optimization of the operating processes (flocculant dose, pH and stirring speed) was performed by using Box–Behnken design (BBD) to evaluate the removal efficiency of POPs. A partial cubic equation could model the bisphenol A and DEHP removal with R2 values of 0.928 and 0.9732, respectively. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to study the morphological structure and functional groups of the treated flocs. SEM micrographs revealed porous and rough cloudy surface in the LBG-treated flocs compared to alum. FTIR analysis indicated the presence of carboxyl, hydroxyl and amino groups as well as hydrogen bonding that are flocculating agents, which act as a bridging agent for the pollutant particles and encouraged aggregation to form flocs. At the optimal conditions of pH 7.5 and LBG dosage of 500 mg/L, removal efficiencies obtained were 76 and 69% for bisphenol A and DEHP, respectively. Results indicated that coagulation–flocculation using LBG can be highly effective in treating POPs from landfill leachate.