王子丹,Hameed Sohaib,张诺伟*,陈秉辉

(厦门大学 化学化工学院,醇醚酯化工清洁生产国家工程实验室,福建 厦门 361005)

催化湿式氧化; PdNi/C; 氨氮废水

Efficient Harmless-degrading of Ammonia by Catalytic Wet Air Oxidation with PdNi/C Catalyst Under Mild Conditions
WANG Zidan,HAMEED Sohaib,ZHANG Nuowei*,CHEN Binghui

(National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China)

catalytic wet air oxidation(CWAO); PdNi/C; ammonia nitrogen wastewater

DOI: 10.6043/j.issn.0438-0479.201703034


氨氮废水对环境的危害日益严重,催化湿式氧化技术能高效无害化处理氨氮废水,但现有催化剂工作条件苛刻.采用化学还原法制备2%Pd1%Ni/C双金属催化剂,并考察了其氨氮废水催化湿式氧化性能.结果表明:Pd和Ni的结合使得PdNi/C催化剂在更低贵金属用量的前提下,比相对应的单贵金属催化剂(Pd/C)具有更优的催化性能,尤其是低温催化性能.在每千克催化剂每小时处理约33 L模拟废水(氨氮的质量浓度为1 000 mg/L,pH=12)及反应压强为2 MPa处理3 h的条件下:在140 ℃时,2%Pd1%Ni/C催化剂能催化氧化脱除废水中99.0%的氨氮,且N2选择性为90.5%; 而3%Pd/C 和3%Ni/C催化剂的氨氮转化率仅分别为86.4%和50.6%; 即使在120 ℃的温和条件下,采用2%Pd1%Ni/C催化剂也能脱除80%以上的氨氮.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、CO程序升温还原(CO-TPR)对PdNi/C催化剂进行表征,结果表明Pd和Ni之间的协同作用调变了催化剂的亲氧性能,进而提高了氨氮转化率.

The pollution of wastewater containing ammonia becomes more and more serious.Ammonia can be efficiently removed by catalytic wet air oxidation(CWAO)technology.However,most of CWAO processes are operated at high pressures and temperatures,because the applied catalysts exhibited poor catalytic prefromance under mild conditions.In this study,PdNi/C bimetallic catalyst was prepared via a chemical reduction method and investigated for CWAO of ammonia to N2.It is found that the combining of Pd and Ni enables PdNi/C bimetallic catalyst to possess higher catalytic performance,especially at low temperatures,although it contains a lower Pd loading,compared with Pd/C.At 140 ℃,almost 100% ammonia can be removed by 2%Pd1%Ni/C bimetallic catalyst,while only 86.4% and 50.6% can be removed respectively with 3%Pd/C and 3%Ni/C,under the capacity around 33 L wastewater(ρ0NH3=1 000 mg/L,pH=12)per kilo catalyst per hour with the pressure of 2 MPa conduct for 3 h.Even at 120 ℃,more than 80% ammonia can be removed using 2%Pd 1%Ni/C.Moreover,the selectivity to N2 for 2%Pd1%Ni/C is higher than 90%.The characterization results of X-ray diffraction(XRD),CO temperature programmed reduction(CO-TPR)and X-ray photo-electron spectroscopy(XPS)indicate that the synergy between Pd and Ni modifies the redox properties and thus promotes the catalytic performance.