Simultaneous Removal of Inorganic and Organic Pollutants from Polycontaminated Wastewaters on Modified Hemp-Based Felts

In this study, an adsorption process using hemp-based materials in felt form was applied to remove between 45 and 53 contaminants present in wastewater from the surface treatment industry. Several materials were compared using batch experiments, including a felt made of 100% hemp fiber (HEMP), the same felt cross-linked with 1,2,3,4-butanetetracarboxylic acid (HEMPBA), a felt coated with a maltodextrin-1,2,3,4-butanetetracarboxylic cross-linked polymer (HEMPM), and a felt coated with hydroxypropyl-a-cyclodextrin-1,2,3,4-butanetetra-carboxylic cross-linked polymer (HEMPCD). Chemical analysis showed that HEMPBA, HEMPM and HEMPCD materials had high adsorption capacities on metals in wastewater, confirming the role of carboxylic groups. Only HEMPCD was able to remove both metals and organics, resulting in the virtual elimination of organics such as chloroform, 1,2-dichlorobenzene, and nonylphenol. This result demonstrated the important role of cyclodextrin molecules in adsorption mechanism. HEMPCD also resulted in an important decrease in residual chemical oxygen demand and total organic carbon of more than 83% and 53%, respectively, while the treatment with HEMP lowered them by 12% and 12%, HEMPBA by 9% and 7%, and HEMPM by 45% and 26%. Chemical abatement and toxicity mitigation have demonstrated that adsorption onto a non-conventional material could be an interesting treatment step for the detoxification of wastewater.