碱改性污泥生物炭活化过氧乙酸降解磺胺甲噁唑

Degradation of sulfamethoxazole with peroxyacetic acid activated by alkali-modified sludge biochar

以城市污水厂污泥为原料,在800℃下限氧热解制备污泥生物炭,使用氢氧化钠改性得到碱改性污泥生物炭(N-SDBC),并作为催化剂活化过氧乙酸(PAA)降解磺胺甲噁唑(SMX)。通过SEM、FTIR、BET以及酸碱电位法对催化剂进行表征,并考察了氧化剂浓度、催化剂投加量、初始pH、水体中常见阴离子和腐殖酸对SMX降解性能的影响。结果表明,在PAA浓度为1.0 mmol/L,N-SDBC质量浓度为1.5 g/L,初始pH为3.0的条件下,90 min内SMX的降解率达到83.8%;水体中的共存阴离子和腐殖酸对SMX降解有不同程度的抑制作用。猝灭实验和电化学测试结果表明,·OH和^(1)O_(2)是体系中主要的活性氧物种,且N-SDBC/PAA体系在降解SMX时存在电子转移机制。经过4次再生循环实验,N-SDBC活化PAA降解SMX的去除率保持在70%以上,说明N-SDBC具有较好的稳定性。

Sludge biochar was prepared from municipal sewage sludge by oxygen-limited pyrolysis at 800℃,and modified with sodium hydroxide to obtain alkali-modified sludge biochar(N-SDBC)as a catalyst to activate peroxyacetic acid(PAA)for the degradation of sulfamethoxazole(SMX).The catalyst was characterized by SEM,FTIR,BET,and acid-base potential methods.The effects of oxidant concentration,catalyst dosage,initial pH,common anions in water,and humic acid on the degradation performance of SMX were investigated.The results showed that the degradation rate of SMX reached 83.8%in 90 minutes under the conditions of N-SDBC mass concentration of 1.5 g/L,PAA concentration of 1.0 mmol/L,and initial pH of 3.0.The coexisting anions and humic acids in the water body inhibited the degradation of SMX to different degrees.The results of the bursting experiments and electrochemical tests showed that·OH and ^(1)O_(2) were the main reactive oxygen species in the system,and there was an electron transfer mechanism in the N-SDBC/PAA system for the degradation of SMX.After four reused tests,the removal rate of SMX was maintained above 70%,indicating that N-SDBC had good stability.