不同结构有机磷在(氢)氧化铝表面的吸附与解吸特征

Sorption and Desorption Characteristics of Different Structures of Organic Phosphorus onto Aluminum ( Oxyhydr) Oxides

研究了4种不同分子结构的有机磷[甘油磷酸（GP）、葡萄糖六磷酸（G6P）、三磷酸腺苷（ATP）和肌-肌醇六磷酸（植酸，IHP）]在无定形Al（OH）3、勃姆石和α—Al2O3等3种（氢）氧化铝表面的吸附解吸特征，并探讨了相关机制．结果表明，单位质量（氢）氧化铝对有机磷最大吸附量顺序为：无定形Al（OH），〉勃姆石〉α-Al2O3，这与矿物的结晶度和表面异质性有关．除IHP在无定形Al（OH），上的吸附外，有机磷在（氢）氧化铝表面的吸附密度随相对分子质量增大而减小：GP〉G6P〉ATP〉IHP．而无定形Al（OH），对最大分子尺寸的IHP吸附量却远大于其他有机磷，这是由于IHP表面络合物转化成了表面沉淀，大大促进了吸附．吸附动力学表明，有机磷吸附起始经历快速吸附阶段，极短时间内达到一定的吸附量，随后是一个较长时间的慢吸附过程，无定形Al（OH），对有机磷的起始快速吸附密度最大，不同有机磷在铝氧化物表面的起始快速吸附密度与相对分子质量呈反比．KCI和柠檬酸对有机磷的解吸能力取决于磷化合物和勃姆石的表面亲和力．KCl初始解吸率大小顺序是：G6P（10．53％）〉GP（6．91％）〉ATP（3．06％）〉IHP（0．8％）．柠檬酸对有机磷的最大解吸率是KCl的4～5倍．KCl对磷的解吸过程经历了几个小时的快速解吸后达到最大解吸率，随后是慢速的扩散再吸附，解吸率反而逐渐下降．对IHP，除扩散再吸附外，表面沉淀也促进了再吸附．因此，有机磷与（氢）氧化铝界面发生较强的专性吸附反应，其分子结构和尺寸以及矿物的结晶度和晶体结构等是影响有机磷的界面反应和环境行为的重要因素．

The sorption and desorption characteristics of four kinds of organic phosphorus with different molecular structures （glycerophosphate （GP）, glucose-6-phosphate （G6P） , adenosine triphosphate （ATP）, and myo-inositol hexakisphosphate （IHP）） on three kinds of aluminum （oxyhydr）oxides （amorphous Al（OH）3, boehmite, and α-Al2O3 ） were studied. The underlying mechanisms were also illustrated. Results showed that the maximum sorption amounts of OP onto Al （oxyhydr）oxides, on a per gram dry weight basis, decreased as following： amorphous Al（OH） 3 〉 boehmite 〉α-Al2O3. This mainly related to the mineral crystallinity and surface heterogeneity. With the exception of sorption of IHP on amorphous Al （OH） 3, the maximum sorption density decreased with increasing molecular weight （MW） of OP, following the order： GP 〉 G6P 〉 ATP 〉 IHP. However, the sorption amount of IHP on amorphous Al（OH）3 was much higher than those of other OP, due to the transformation of surface complexes of IHP to surface precipitation and thus enhancing the sorption. The sorption kinetics results showed that sorption of OP underwent the first onset rapid sorption, i. e. a certain amount of sorption occurred within an onset extremely short period, and a following long and slow sorption process. Amorphous Al （OH）3 had the greatest onset rapid sorption density, and the onset rapid sorption density of OP on Al （oxyhydr） oxides decreased with increasing MW. Desorption capacities of OP by KC1 and citrate solutions related to the surface affinity between OP and boehmite. Initial desorption percentages by KC1 decreased in the order： G6P （10. 53% ） 〉 GP（6.91% ） 〉 ATP （3.06%） 〉 IHP （0. 8% ）. The maximum desorption percentages of OP by citrate were 4-5 times greater than those by KCI. During resorption process of P by KC1, the maximum desorption rate achieved after a fast desorption in a few hours, followed by diffusion- resorption during which the desorption percentage gradually decreased. Specially, both diffusion-resorption and surface precipitation promoted the resorption of IHP on mineral surface. Conclusively, the strong specific sorption of OP occurs on the surface of Al （oxyhydr） oxides, and molecular structure and size of OP as well as the crystallinity and crystal structure of minerals are the key factors affecting the interfacial reactions and environmental behaviors of OP.