Enhanced soil washing process for the remediation of PBDEs/Pb/Cd-contaminated electronic waste site with carboxymethyl chitosan in a sunflower oil–water solven...

Abstract

Abstract An innovative ex situ soil washing technology was developed to remediate polybrominated diphenyl ethers (PBDEs) and heavy metals in an electronic waste site. Elevated temperature (50° C) in combination with ultrasonication (40 kHz, 20 min) at 5.0 mL L− 1 sunflower oil and 2.5 g L− 1 carboxymethyl chitosan were found to be effective in extracting mixed pollutants from soil. After two successive washing cycles, the removal efficiency rates for total PBDEs, BDE28, BDE47, BDE209, Pb, and Cd were approximately 94.1, 93.4, 94.3, 99.1, 89.3, and 92.7%, respectively. Treating the second washed soil with PBDE-degrading bacteria (Rhodococcus sp. strain RHA1) inoculation and nutrient addition for 3 months led to maximum biodegradation rates of 37.3, 52.6, 23.9, and 1.3% of the remaining total PBDEs, BDE28, BDE47, BDE209, respectively. After the combined …