The present study investigates the applicability of Fenton's oxidation for the treatment of a highly refractory, viscous, bulk drug industry effluent. The effluent is found to behave as a Newtonian fluid, thrice as viscous as water. Fenton's oxidation experiments on the undiluted effluent are conducted in accordance with central composite design (CCD), considering the operating factors of pH (3–11), FeSO₄ dosage (3–15 g L⁻¹), H₂O₂ dosage (7–19 mL L⁻¹), and treatment time (30–150 min). The treatment yielded a maximum total organic carbon (TOC) reduction of 28% at neutral pH, FeSO₄, and H₂O₂ dosages of 9 g L⁻¹ and 13 mL L⁻¹, respectively, for 150 min of operation. The maximal treatment efficacy observed at neutral pH is explained by the non‐radical mechanism of Fenton's oxidation, and further correlated with viscosity and type of fluid (here, Newtonian), as judged from the generated viscosity profiles. Upon comparison with previous effluent samplings, differing treatment efficacies are observed for different fluid types, that is, Newtonian and non‐Newtonian (shear thinning), with the latter obtaining twice the TOC reduction, under similar experimental conditions. Hence, the effect of viscosity and fluid type on the effectiveness of Fenton's oxidation treatment is experimentally validated and discussed.

中文翻译：

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Fenton氧化处理对粘度曲线相反的制药工业废水的影响

本研究调查了芬顿氧化法在治疗高难，粘稠，原料药工业废水中的适用性。发现流出物表现为牛顿流体，粘性像水一样三次。考虑到pH（3-11），FeSO ₄剂量（3-15 g L ^-1），H ₂ O ₂剂量（3）的操作因素，Fenton对未稀释废水进行氧化实验是根据中央复合设计（CCD）进行的7–19 mL L ^-1）和处理时间（30–150分钟）。该处理在中性pH，FeSO ₄和H ₂ O ₂剂量为9 g L ^-1时产生最大总有机碳（TOC）降低28％和13 mL L ^-1分别运行150分钟。Fenton氧化的非自由基机理解释了在中性pH值下观察到的最大治疗功效，并根据生成的粘度曲线进一步将其与粘度和流体类型（此处为牛顿）相关。与以前的废水采样进行比较后，对于不同的流体类型，即牛顿型和非牛顿型（剪切稀化），观察到了不同的处理效果，在相似的实验条件下，后者获得了两倍的总有机碳减少量。因此，实验验证和讨论了粘度和流体类型对Fenton氧化处理效果的影响。