生物炭与微量铁共催化降解水中磺胺二甲基嘧啶

Biocharand Trace Iron Co-catalyzed Degradation of Sulfamethazine in Water

采用生物炭(BC)与微量溶解态Fe(Ⅱ)/Fe(Ⅲ)共同催化芬顿反应降解水中磺胺二甲基嘧啶(SMZ),目的在于加速污染物降解的同时控制含铁污泥的产生。结果表明,当初始pH 3.0时,BC(1.0 g·L^(-1))与微量Fe(Ⅱ)(1.0 mg·L^(-1))构成的复合芬顿体系中SMZ的降解速率常数(k_(obs))分别是BC+H_(2)O_(2)和Fe(Ⅱ)+H_(2)O_(2)体系的20.0倍和14.1倍;且在Fe(Ⅱ)剂量低至0.3 mg·L^(-1)时,BC+Fe(Ⅱ)+H_(2)O_(2)体系仍能在120 min内使SMZ接近完全转化。由于生物炭对Fe(Ⅲ)的还原,采用微量Fe(Ⅲ)代替Fe(Ⅱ)后复合体系中SMZ仍保持相当高的降解速率。通过测定·OH累计产量和H_(2)O_(2)消耗量,表明复合体系中生物炭可以催化H_(2)O_(2)分解、而微量Fe(Ⅱ)/Fe(Ⅲ)提高了·OH产率,两者的共催化作用加速了污染物降解。

Biochar(BC)and trace dissolved Fe(Ⅱ)/Fe(Ⅲ)were used together to catalyze the Fenton reactions for degradation of sulfamethazine(SMZ)in water,aiming at accelerating the degradation of pollutants while controlling the production of iron sludge.The results indicated that at the initial pH 3.0,the degradation rate constant(k_(obs))of SMZ in the composite Fenton system composed of BC and trace Fe(Ⅱ)(1.0 mg·L^(-1))was 20.0 times that in BC+H_(2)O_(2),and 14.1 times that in Fe(Ⅱ)+H_(2)O_(2),respectively.SMZ was almost completely transformed within 120 min in BC+Fe(Ⅱ)+H_(2)O_(2),even with a Fe(Ⅱ)dosage as low as 0.3 mg·L^(-1).Due to the reduction of Fe(Ⅲ)by biochar,SMZ was degraded with a comparably high rate when trace Fe(Ⅲ)was used instead of Fe(Ⅱ).The results obtained by measurement of cumulative production of·OH and consumption of H_(2)O_(2)showed that in the composite system biochar could accelerate the decomposition of H_(2)O_(2),while trace Fe(Ⅱ)/Fe(Ⅲ)enhanced the yield of·OH,so their co-catalysis effect accelerated the degradation of pollutants.