REMOVAL OF NITRATE FROM DRINKING WATER BY USING PdCu STRUCTURED CATALYSTS BASED ON CORDIERITE MONOLITHS

Abstract Structured catalysts were prepared, characterized and evaluated in NO3 - removal from drinking water. Different suspensions containing a previously optimized PdCu/5wt% ZrO2-Al2O3 powder catalyst (hereinafter PdCu/5ZAp) were prepared and deposited on cordierite monoliths by washcoating. The effect of suspension concentration, the particle size, the immersion number, the use of suspension stabilizer agent, and an alumina pre-coating on the coating adherence and catalytic performance were studied. All the prepared structured catalysts were active for the elimination of NO3 - and presented good selectivity to N2 (> 93%) in synthetic water samples. The catalyst performance was related to the amount of deposited catalyst. The highest activity and the best coating adherence were obtained with the structured catalyst prepared by a single immersion in a 14 wt% concentration suspension, which was obtained from the powder catalyst milled for 10 h and stabilized with colloidal alumina. This catalyst also showed good activity when it was reused for four cycles and when it was evaluated with real water samples.

摘要：本研究制备并表征了结构化催化剂，并针对其用于饮用水脱除硝酸根（NO₃⁻）的性能开展评估。本研究制备了多组含预先优化的钯铜/5wt%氧化锆-氧化铝（PdCu/5wt% ZrO₂-Al₂O₃，下称PdCu/5ZAp）粉体催化剂的悬浮液，通过涂覆法将其负载于堇青石整体式载体上。考察了悬浮液浓度、粉体粒径、浸渍次数、悬浮液稳定剂的使用以及氧化铝预涂覆工艺对涂层附着力与催化性能的影响。所有制备得到的结构化催化剂均可有效脱除硝酸根，且在合成水样中对氮气（N₂）的选择性均高于93%。催化剂的催化性能与负载量呈显著相关关系。采用经10小时球磨的粉体催化剂与胶态氧化铝稳定配制的14wt%浓度悬浮液，经单次浸渍制备的结构化催化剂，展现出最高的催化活性与最优的涂层附着力。该催化剂经四次循环使用后仍保持良好活性，且在实际水样测试中亦表现出优异的催化性能。