Synergistic advanced oxidation process for enhanced degradation of organic pollutants in spent sulfuric acid over recoverable apricot shell-derived biochar catalyst.

The sulfuric acid-based alkylation process, which leads the industrial application market, still struggles with effectively removing a large number of organic pollutants from hazardous spent sulfuric acid. A synergistic advanced oxidation process was constructed to degrade the organic pollutants with H 2 O 2 and sodium persulfate as the synergistic oxidants and apricot shell-derived biochar (OBC) as the catalyst. Taking the total organic carbon (TOC) and the color scale as the indices, the effects of critical experimental factors, i.e. , reaction temperature, initial oxidant concentration, catalyst dosage, and aeration rate, were optimized. The results showed that the removal rates of TOC and the color of the spent sulfuric acid reached ∼91% and 96.6%, respectively, after 150 min under the optimum conditions. Besides, the efficient and low-cost OBC catalyst developed in this study could be continuously used for at least four times with about 75% TOC removal and 80% color removal, exhibiting favorable stability and good resistance to acid corrosion. Further study confirmed that the SO 4 -˙ and ˙OH radicals generated in the synergistic advanced oxidation process strengthened the degradation and elimination of organic pollutants. The synergistic advanced oxidation process could provide a feasible insight for spent sulfuric acid treatment.