硅藻土原位生长Nb2O5纳米棒及表面Cr(VI)吸附转化行为研究

以活化铌酸为铌源, 草酸铵为沉积剂, 十二烷基苯磺酸钠为模板剂, 采用水热法在硅藻土表面原位生长Nb₂O₅纳米棒。采用SEM、TEM、XRD、BET、FT-IR和XPS等分析方法对样品进行表征, 反应14 h后, Nb₂O₅纳米棒长度为500~700 nm, 直径为25~35 nm; 硅藻土原位生长Nb₂O₅纳米棒样品比表面积为157 m²/g。研究了样品对Cr(VI)的吸附与光还原行为, 可见光条件下对Cr(VI)吸附量可达220 mg/g; 紫外光条件下, 可将表面吸附的Cr(VI)转变为Cr(III), 样品经过5次循环使用后, 对Cr(VI)(100 mg/L)降解率仍能保持在93%左右。样品可对重金属污染废水中Cr(VI)进行吸附与毒性降解一体化去除。

In-situ Growth of Nb2O5 Nanorods on Diatomite and Highly Effective Removal of Cr(VI)

Nb₂O₅ nanorods decorated diatomite were synthesized via a hydrothermal method by using niobic acid, ammonium oxalate and sodium dodecyl benzene sulfonate (SDBS). The as-prepared samples were characterized by SEM, TEM, XRD, BET, and FT-IR techniques. The Nb₂O₅ nanorod was obtained with length of 500~700 nm and diameter of 25~35 nm. BET test showed that specific surface area of Nb₂O₅ nanorods decorated diatomite reached 157 m²/g which show a high adsorbance tendence. Under visible light irradiation, the adsorption capacity for Cr (VI) could be 220 mg/g. With the assistance of UV-light photoreduction, the maximum removal capacity for Cr (VI) could be 340 mg/g, and the absorbed Cr(VI) was transformed to Cr(III). After photodegradation for five times, the degradation rate of Cr(VI) (100 mg/L) were still at about 93%. Nb₂O₅ nanorods/diatomite could adsorb Cr(VI) from sewage effectively and in the meantime accomplish the toxicity degradation, showing a promising treatment of Cr(VI) containing waste water.