Influence of heavy metal and cationic surfactants on biodegradation of phenol with bentonite

Abstract

To study the feasibility of organobentonite modified with hexadecyltrimethylammonium (HDTMA) as an immobilizing barrier for mixed wastes, the interactions of heavy metals, organic contaminants, and soil microorganisms were investigated when they coexist with organobentonite. At low concentrations (<50μM), heavy metal ions slightly reduced the growth of soil microbes and partially interfere the biodegradation of phenol. Soil microorganisms with bentonite grew after approximately 25 hours of lag period and degraded phenol within 350 hours. However, the number of soil microorganisms with HDTMA-bentonite was reduced due to the toxicity of desorbed HDTMA. On the other hand, dioctadecyltrimethylammonium (DODMA) and dihexadecyldimethylammonium (DHDMA) exerted little toxicity to soil microbes except for minor decreases in the rate of phenol biodegradation.