Adsorption studies of hexavalent chromium [Cr (VI)] on micro-scale biomass of Sargassum dentifolium, Seaweed

Abstract

Hexavalent chromium [Cr (VI)] is known as the most toxic form of chromium compounds. It had many hazardous effects on the human health and the environment. Therefore, the objective of this study aimed to remove toxic Cr (VI) from an aqueous solution using pre-treated biomass of marine brown algae Sargassum dentifolium (grinded to micro-size scale). Optimization for Cr (VI) removal efficiency (CRE) was performed through One Factor at A time experiments (OFAT) to determine the low and the high level of each factor. Afterwards, a full factorial experimental design (Many interacted factors at a time) was applied in order to determine the optimum conditions that maximize the CRE. The results of the response optimizer model suggested that the highest removal efficiency of 99.68% can be achieved by applying 1.5 g/ 100 /ml of 0.3868 μm dried algae biomass to 100 ppm Cr-contaminated wastewater with a novel model [contact time flocculation state (CFTs)] for 1 h shaking continued to12 h static, at pH 7.0, and 50 °C. Linear Langmuir and Freundlich isotherm were displayed, and results stated that Langmuir isotherm more applicable to this process which suggested a monolayer adsorption nature of the biosorbent surface.