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Nitrite removal from water by catalytic hydrogenation in a Pd‐ CNTs / Al 2 O 3 hollow fiber membrane reactor
Author(s) -
Zhao Zihang,
Tong Gonghe,
Tan Xiaoyao
Publication year - 2016
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.4816
Subject(s) - nitrite , catalysis , chemistry , inorganic chemistry , membrane reactor , chemical engineering , hydrogen , adsorption , aqueous solution , dissolution , noble metal , nitrate , organic chemistry , engineering
BACKGROUND Nitrite contaminants in groundwater endanger public health since they may cause many diseases such as blue baby syndrome, cancer and hypertension. In this work, novel Pd‐ CNTs / Al 2 O 3 catalytic hollow fiber membranes for aqueous nitrite hydrogenation reduction were fabricated by the deposition of carbon nanotubes ( CNTs ) and Pd nanoparticles inside porous Al 2 O 3 hollow fibers. A hollow fiber membrane reactor was assembled for nitrite removal from water by catalytic hydrogenation reduction. RESULTS Experimental results indicated that the nitrite hydrogenation rate was highly dependent on hydrogen dissolution in water and adsorption on the catalyst. The nitrite removal increased with increasing H 2 partial pressure to balance the nitrite solution, but the influence became very marginal as it approached 1.0 atm. The oxygen in the gas feed lowered the nitrite removal due to the reaction with dissolved hydrogen over the Pd‐catalyst. Compared with the conventional diffusion operation of the membrane reactor, the ‘flow‐through’ operation resulted in higher nitrite removals due to the intensified mass transfer rate. CONCLUSION The nitrites in water can be completely removed using the Pd‐ CNTs / Al 2 O 3 membrane reactor with flow‐through operation. The denitrification should be operated at around 25°C for large reaction kinetics, which is determined by both the temperature and the hydrogen solubility in water. © 2015 Society of Chemical Industry