Comparative study of diethyl phthalate degradation by UV/H2O2 and UV/TiO2: kinetics, mechanism, and effects of operational parameters
2016
Song, Chengjie | Wang, Liping | Ren, Jie | Lv, Bo | Sun, Zhonghao | Yan, Jing | Li, Xinying | Liu, Jingjing
The photodegradation of diethyl phthalate (DEP) by UV/H₂O₂ and UV/TiO₂ is studied. The DEP degradation kinetics and multiple crucial factors effecting the clearance of DEP are investigated, including initial DEP concentration ([DEP]₀), initial pH values (pH₀), UV light intensity, anions (Cl⁻, NO³⁻, SO₄ ²⁻, HCO₃ ⁻, and CO₃ ²⁻), cations (Mg²⁺, Ca²⁺, Mn²⁺, and Fe³⁺), and humic acid (HA). Total organic carbon (TOC) removal is tested by two treatments. And, cytotoxicity evolution of DEP degradation intermediates is detected. The relationship between molar ratio ([H₂O₂]/[DEP] or [TiO₂]/[DEP]) and degradation kinetic constant (K) is also studied. And, the cytotoxicity tests of DEP and its degradation intermediates in UV/H₂O₂ and UV/TiO₂ treatments are researched. The DEP removal efficiency of UV/H₂O₂ treatment is higher than UV/TiO₂ treatment. The DEP degradation fitted a pseudo-first-order kinetic pattern under experimental conditions. The K linearly related with molar ratio in UV/H₂O₂ treatment while nature exponential relationship is observed in the case of UV/TiO₂. However, K fitted corresponding trends better in H₂O₂ treatment than in TiO₂ treatment. The Cl⁻ is in favor of the DEP degradation in UV/H₂O₂ treatment; in contrast, it is disadvantageous to the DEP degradation in UV/TiO₂ treatment. Other anions are all disadvantageous to the DEP degradation in two treatments. Fe³⁺ promotes the degradation rates significantly. And, all other cations in question inhibit the degradation of DEP. HA hinders DEP degradation in two treatments. The intermediates of DEP degradation in UV/TiO₂ treatment are less toxic to biological cell than that in UV/H₂O₂ treatment.
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