Palm oil mill secondary effluent treatment using ZNO-clay liquid photocatalyst in membrane photocatalytic reactor

In recent years, photocatalytic treatment of palm oil mill secondary mill effluent (POMSE) incorporating ZnO nanoparticles with various types of capping agents via membrane photocatalytic reactor (MPR) has gained great interest among researchers. Nevertheless, most of previous studies have employed a rather time-consuming oven drying and calcination method to synthesise ZnO in powder form. Therefore, a simpler synthesis method is considered necessary. In this study, ZnO-clay was synthesised in liquid form using the precipitation method, without undergoing oven drying and calcination. The effect of different ZnO-clay ratios on the degradation performance of POMSE via MPR was also examined. Results indicated that ZnO-clay 1:3 was efficient in BOD removal percentage, while the removal percentages of COD, colour and turbidity were higher for ZnO-clay 1:5 compared to other ratios. [Display omitted] •Liquid form of ZnO-clay was synthesized using simple method.•ZnO-clay in liquid form was used as photocatalyst to degrade POMSE.•1:3 ratio of ZnO-clay shows the highest degradation rate in MPR.