Hashimoto Yohey, Sato Takeshi
Department of Civil Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Chemosphere. 2007 Nov;69(11):1775-82. doi: 10.1016/j.chemosphere.2007.05.055. Epub 2007 Jul 2.
The use of a phosphorus amendment in altering Pb to a chemically less mobile phase is a promising strategy based on minimizing ecotoxicological risk and improving time and cost efficiency. This study evaluated crystalline and poorly-crystalline hydroxyapatite sorbents on removal of aqueous Pb in response to reaction time, solution pH, and Pb concentration. Batch experiments were conducted using a commercially-available crystalline hydroxyapatite (HA), and two poorly-crystalline hydroxyapatites synthesized from gypsum waste (CHA) and incinerated ash of poultry waste (MHA). Poorly-crystalline hydroxyapatites had greater capacity for Pb removal from a solution with a wider pH range as compared to a crystalline hydroxyapatite. The maximum sorption capacity of Pb determined by the Langmuir model was 500 mg g(-1) for CHA, 277 mg g(-1) for MHA and 145 mg g(-1) for HA. Removal of aqueous Pb by CHA was not dependent on solution pH, with a 98.8% reduction throughout the solution pH range of 2-9, whereas aqueous Pb removal by HA and MHA was pH-dependent with less removal in the neutral solution pH. Poorly-crystalline hydroxyapatites may provide an effective alternative to existing remediation technologies for Pb-contaminated sites.
基于将生态毒理学风险降至最低并提高时间和成本效率，使用磷改良剂将铅转变为化学活性较低的相是一种很有前景的策略。本研究评估了结晶态和低结晶度的羟基磷灰石吸附剂在反应时间、溶液pH值和铅浓度作用下对水中铅的去除效果。使用市售的结晶态羟基磷灰石（HA）以及由石膏废料合成的两种低结晶度羟基磷灰石（CHA）和家禽粪便焚烧灰合成的低结晶度羟基磷灰石（MHA）进行了批量实验。与结晶态羟基磷灰石相比，低结晶度羟基磷灰石在更宽的pH值范围内从溶液中去除铅的能力更强。由朗缪尔模型确定的CHA对铅的最大吸附容量为500 mg g(-1)，MHA为277 mg g(-1)，HA为145 mg g(-1)。CHA对水中铅的去除不依赖于溶液pH值，在2-9的整个溶液pH值范围内去除率为98.8%，而HA和MHA对水中铅的去除则依赖于pH值，在中性溶液pH值下去除率较低。低结晶度羟基磷灰石可能为铅污染场地的现有修复技术提供一种有效的替代方法。
