Removal of Methylene Blue from aqueous solutions by adsorption on Kaolin: Kinetic and equilibrium studies

Abstract

Microwave assisted extraction (MAE) was investigated for extraction of total phenolic compounds (TPC expressed as gallic acid equivalents GAE) from the leaves of Pistacia lentiscus L. with maximized total phenolic yield using response surface methodology (RSM) coupled with a Box–Behnken design. The optimal MAE processing parameters were 46% ethanol, extraction time 60 s, potency density 17.86 W/mL, and liquid/solid ratio 28:1, with an extraction yield of 185.69 ± 18.35 mgGAE/gdw. The optimized MAE was compared with another emerging technology (ultrasound assisted extraction, UAE) and with conventional solvent extraction (CSE) giving higher extraction yields of TPC, total flavonoids and tannins and comparable antioxidant capacity (according to the radical ABTS assay).