针铁矿对羟基磷灰石溶解的影响

Effects of Goethite on the Dissolution of Hydroxyapatite

如今,磷基钝化材料已被广泛应用于重金属污染土壤的治理与修复中,但南方红壤中含有的大量铁氧化物能够与磷结合,会影响磷基材料的溶解特性。以磷基材料羟基磷灰石(HAP)和针铁矿(GTT)为研究对象,考察不同用量的GTT对HAP在溶液中的溶解动力学以及不同p H对HAP溶解的影响。结果表明,HAP的溶解是一个缓慢的过程。期间,溶液p H与磷酸盐表现为先增加,进而趋于平缓,并再次出现增加的趋势。随着针铁矿用量的增加,磷酸盐含量显著降低,但未显著影响溶液pH。提高溶液pH,降低了HAP溶解释放的磷酸盐,且同一pH下,高用量的GTT更利于溶液pH的增加和磷酸盐含量的降低。由此可见,针铁矿能够有效吸附固定磷酸盐,促进羟基磷灰石的溶解。

Phosphorus-based materials are widely used in remediation of heavy metals contaminated soil,but a large number of iron oxides in red soil in southern China may combine with phosphorus,which may affect the solubility characteristics of phosphorus-based materials.The effects of goethite(GTT)on the dissolution kinetics of hydroxyapatite(HAP)in solution under various dosage and pHconditionswere investigated in this paper.The results showed that the dissolution of HAP was a slow process.Solution pH and phosphate content increased first,then maintained stable level and increased again during the dissolution process.With the increase of GTT dosages,the phosphate content decreased significantly,but did not significantly affect the solution pH.Increasing the solution pH reduces the phosphate released by HAP dissolution.Moreover,high dosage of GTT is more effective to increase solution pH and to decrease the phosphate content under the same pH.The above results show that goethite can effectively adsorb and fix phosphate and promote the dissolution of HAP.