Preparation of Amphiphilic Chitosan-Loaded Bentonite Adsorbent and Its Performance in Removing Organic Matter from Coking Wastewater.

An amphiphilic chitosan-loaded bentonite adsorbent (C18CTS-BT) was prepared for the efficient removal of organic matter from coking wastewater. The structure and surface morphology of adsorbents were characterized by FT-IR, XRD, and SEM. The removal of those organics by C18CTS-BT was investigated by comparing the adsorption performances of C18CTS-BT with bentonite (BT) and chitosan-loaded bentonite (CTS-BT). The results showed that compared with BT and CTS-BT, C18CTS-BT showed the performance advantages of having a low dosage, wide pH range, and short adsorption equilibrium time. The optimized treatment process was as follows: the adsorbent dosage was 1.5 g·L, the adsorption time was 60 min, and the pH of the system was 7.0. The chemical oxygen demand (COD) of the coking wastewater treated with BT, CTS-BT, and C18CTS-BT decreased from 342 mg·L in the raw water to 264 mg·L, 218 mg·L, and 146 mg·L, corresponding to COD removal rates of 22.81%, 36.26%, and 57.31%, respectively. The results of GC-MS analysis also confirmed that C18CTS-BT could remove most of the organic compounds in coking wastewater, especially long-chain alkanes and their derivatives. The hydrophobic modification of the adsorbent material can effectively improve the removal performance of organic compounds from coking wastewater.