Abstract Degradation of dimethoate (DM), an organophosphorus pesticide, present in aqueous solution considered as simulated wastewater was investigated using different approaches based on hydrodynamic cavitation. Initially, the effect of initial concentration of DM was investigated over the range of 20−75 ppm at a constant condition of 4 bar as inlet pressure. The maximum extent of degradation (25 %) was observed for 20 ppm solution using the approach of HC alone. The hybrid approaches of HC + UV, HC+H2O2, and HC + Fenton were subsequently investigated at inlet pressure of 4 bar and pH of 7 (natural pH of solution) using 20 ppm as the initial concentration. Significant increase in degradation for the combination operations such as HC + UV and HC+H2O2 with actual extent of degradation as 30.8 % and 72.5 % respectively was observed. Complete degradation of DM within only 40 min was established in the work using HC + Fenton combination at optimized Fe (II) and H2O2 loadings as 0.9 M and 0.18 M respectively. Also, COD reduction as high as 71.5 % was demonstrated using HC + Fenton combination at much lower Fe (II) and H2O2 loadings as 0.009 M and 0.045 M respectively. The kinetic rate constants were obtained for all treatment approaches using the integral analysis. The toxicity analysis of DM, before and after treatment, was also performed using two bacterial strains as Bacillus subtilis and Pseudomonas aeruginosa. Based on the obtained values of cavitational yield and operational costs based on energy requirements, the different treatment approaches have also been compared. Overall, it was clearly demonstrated that HC + Fenton is an effective treatment approach for the complete remediation of DM and treated effluent also showed no toxicity to the bacteria.

中文翻译：

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使用基于流体动力学空化和高级氧化工艺的组合方法降解乐果

摘要 使用基于流体动力学空化的不同方法研究了乐果 (DM)，一种有机磷农药，存在于被视为模拟废水的水溶液中的降解。最初，在 4 bar 作为入口压力的恒定条件下，研究了 20-75 ppm 范围内 DM 初始浓度的影响。仅使用 HC 的方法观察到 20 ppm 溶液的最大降解程度 (25%)。随后使用 20 ppm 作为初始浓度，在 4 bar 的入口压力和 7（溶液的自然 pH 值）的入口压力下研究了 HC + UV、HC+H2O2 和 HC + Fenton 的混合方法。观察到 HC+UV 和 HC+H2O2 等组合操作的降解显着增加，实际降解程度分别为 30.8% 和 72.5%。使用 HC + Fenton 组合在优化的 Fe (II) 和 H2O2 负载量分别为 0.9 M 和 0.18 M 的情况下，仅在 40 分钟内完全降解 DM。此外，使用 HC + Fenton 组合在更低的 Fe (II) 和 H2O2 负载量（分别为 0.009 M 和 0.045 M）下，COD 降低高达 71.5%。使用积分分析获得所有处理方法的动力学速率常数。DM 在治疗前后的毒性分析也使用两种细菌菌株进行，即枯草芽孢杆菌和铜绿假单胞菌。根据获得的空化产量值和基于能源需求的运营成本，还比较了不同的处理方法。全面的，