聚合钛盐除藻污泥的资源化回收及其光催化性能

Resource utilization and photocatalytic performance of polytitanium salt dealgal sludge

采用一步煅烧法从钛基混凝剂混凝后的富藻污泥中回收制备TiO_(2)纳米颗粒,并经光沉积法制备了Pt负载的TiO_(2)光催化剂(Pt@TiO_(2))。采用XRD、SEM、TEM、EDS、BET对Pt@TiO_(2)进行了表征,结合PL光谱、UV-Vis DRS谱图探究了不同Pt负载量(以TiO_(2)纳米颗粒的质量为基准,下同)Pt@TiO_(2)光催化降解4-氯苯酚(4-CP)的活性,考察了Pt@TiO_(2)用量(即在一定体积4-CP溶液中的加入质量,下同)、4-CP溶液质量浓度、溶液pH、腐植酸质量浓度对4-CP降解率的影响,并考察了最优催化剂的循环稳定性。结果表明,Pt负载量为0.3%的0.3%Pt@TiO_(2)具有最佳的光催化降解4-CP的活性,其为纳米球形(介孔)结构,平均孔径约为10 nm,晶格间距0.350 nm。当4-CP初始质量浓度为20 mg/L、0.3%Pt@TiO_(2)用量为0.5 g/L、pH=7时,催化剂可在60 min内完全降解4-CP。Pt@TiO_(2)光催化降解4-CP的活性物种为羟基自由基和超氧自由基,0.3%Pt@TiO_(2)循环使用5次后,仍可降解92.5%的4-CP。

Pt-loaded TiO_(2) photocatalytic catalyst(Pt@TiO_(2))was obtained via photodeposition of Pt on TiO_(2) nanoparticles,which were prepared from titanium-coagulated algae-rich sludge by one-step calcination method,and characterized by XRD,SEM,TEM,EDS and BET.The photocatalytic performance of Pt@TiO_(2) with different Pt loading amouts(based on the mass of TiO_(2) nanoparticles,the same below)on 4-chloropol(4-CP)degradation was analyzed through PL spectrum and UV-Vis DRS spectrum.The effects of Pt@TiO_(2) dosage(that is,the added mass of 4-CP solution in a certain volume,the same below),4-CP mass concentration,solution pH and humic acid mass concentration on the degradation rate of 4-CP were evaluated,followed by assessment on the cyclic stability of the optimal catalyst.The results indicated that 0.3%Pt@TiO_(2) with 0.3%Pt loading amount exhibited the best photocatalytic activity for the degradation of 4-CP,which had a nanospheroidal(mesoporous)structure with an average pore size of about 10 nm and lattice spacing of 0.350 nm.Under the conditions of 4-CP initial mass concentration 20 mg/L,0.3%Pt@TiO_(2) dosage 0.5 g/L and pH 7,4-CP could be completely degraded within 60 min.The active species of Pt@TiO_(2) photocatalytic degradation on 4-CP were hydroxyl radical and superoxide radical,and 92.5%of 4-CP could still be degraded by 0.3%Pt@TiO_(2) after 5 times of recycling.