砷羟基磷灰石的制备及其砷毒性浸出研究
发布时间：2018-10-24 14:17
【摘要】：砷及其化合物是一类具有高毒害作用的物质,对环境的危害极大,给人类的生存发展造成了严重的威胁。随着高砷产业(采矿、冶金、化工)的迅速发展,砷污染的治理已成为全球的研究热点。现行的许多方法存在着除砷效果差,砷浸出高,长期稳定性不高等弊端,砷的处置急需一种行之有效的方法。由于As0_4~(3-)与PO_4~(3-)性质相近,所以可以形成较为稳定的砷酸盐固溶体,利用无机砷化物的难溶性除砷将是最具潜力的一种方法。本论文通过水热反应制备了砷羟基磷灰石及改性的砷硅羟基磷灰石,并对影响合成的主要因素进行了讨论,制定出最佳合成方案。通过毒性浸出实验,定期测定砷的浸出浓度,对固溶体的稳定性进行了研究。研究结果如下：1、实验采用水热法,以Ca(NO_3)_2·4H_2O、(NH_4)_2HPO_4、Na_3AsO_4·12H_2O以及Si(OCH_2CH_3)_4为原料,成功制备出不同砷含量的砷羟基磷灰石(As-HA)和改性的砷硅羟基磷灰石(As-Si-HA),并通过研究,得到最佳反应条件：水热反应温度为200℃,水热反应时间为8h,最适宜硅掺量为钙硅摩尔比为10：1(y=1),[Ca_(10)(PO_4)_(6-x-y)(AsO_4)_x(SiO4)_y(OH)_(2-y)]。2、通过XRD、SEM、EDS、FTIR等测试手段对As-HA的晶相、化学组成和形貌等进行分析,结果表明：合成的As-HA为不规则块状晶体,As-HA与HA具有相似的晶体结构,砷的掺入未引入其他杂质相,As以AsO_4~(3-)的形式进入到HA晶格中,取代部分PO_4~(3-),最大砷含量为27.720%。3、通过XRD、SEM、EDS、FTIR等测试手段对As-Si-HA的晶相、化学组成和形貌等进行分析,结果表明：合成的As-Si-HA为不规则块状晶体,As-Si-HA与HA具有相似的晶体结构,砷和硅的掺入未引入其他杂质相,As以As0_4~(3-)的形式进入到HA晶格中,取代部分PO_4~(3-), Si以SiO_4~(4-)的形式取代部分PO_4~(3-),并造成OH-的缺失,使结晶度下降。当y=1时,最大砷含量为19.928%。4、砷的浸出浓度受pH值影响很大,在酸性溶液中砷的浸出浓度最高,在中性溶液中砷的浸出浓度最低,证明固溶体在中性环境中更为稳定。5、通过比较As-HA和As-Si-HA在溶液中的砷的浸出浓度,得出As-Si-HA的砷浸出浓度更低,证明As-Si-HA比As-HA具有更稳定的结构。6、砷酸盐固溶体的砷浸出率整体较低,证明制备的固溶体具有较稳定的晶体结构,砷能以有效键合的方式嵌入到羟基磷灰石晶格中。7、通过XRD、SEM、EDS、FTIR等测试手段对溶解后的样品的晶相、化学组成和形貌等进行分析,结果表明,溶解前后固溶体的结构未发生改变。
[Abstract]:Arsenic and its compounds are a class of highly toxic substances, which have great harm to the environment and pose a serious threat to the survival and development of human beings. With the rapid development of high arsenic industry (mining, metallurgy and chemical industry), the treatment of arsenic pollution has become a global research hotspot. Many existing methods have some disadvantages such as poor arsenic removal, high arsenic leaching, low long-term stability, etc. An effective method is urgently needed to dispose arsenic. Because the properties of As0_4~ (3-) and PO_4~ (3-) are similar, a relatively stable arsenate solid solution can be formed. The insoluble removal of arsenic by inorganic arsenide will be the most promising method. In this paper, arsenic-hydroxyapatite and modified arsenic-silico-hydroxyapatite were prepared by hydrothermal reaction. The main factors affecting the synthesis were discussed and the optimum synthesis scheme was worked out. The stability of solid solution was studied by determining the leaching concentration of arsenic by toxicity leaching experiment. The results are as follows: 1. Using Ca (NO_3) _ 24H _ 2O, (NH_4) _ 2HPO _ 4H _ 2O, (NH_4) _ 2HPO _ 4N _ 3AsO _ 4 12H_2O and Si (OCH_2CH_3) _ 4 as raw materials, different arsenic hydroxyapatite (As-HA) and modified arsenic-silico-hydroxyapatite (As-Si-HA) were successfully prepared by hydrothermal method. The optimum reaction conditions were obtained as follows: hydrothermal reaction temperature was 200 鈩，
本文编号：2291645
[Abstract]:Arsenic and its compounds are a class of highly toxic substances, which have great harm to the environment and pose a serious threat to the survival and development of human beings. With the rapid development of high arsenic industry (mining, metallurgy and chemical industry), the treatment of arsenic pollution has become a global research hotspot. Many existing methods have some disadvantages such as poor arsenic removal, high arsenic leaching, low long-term stability, etc. An effective method is urgently needed to dispose arsenic. Because the properties of As0_4~ (3-) and PO_4~ (3-) are similar, a relatively stable arsenate solid solution can be formed. The insoluble removal of arsenic by inorganic arsenide will be the most promising method. In this paper, arsenic-hydroxyapatite and modified arsenic-silico-hydroxyapatite were prepared by hydrothermal reaction. The main factors affecting the synthesis were discussed and the optimum synthesis scheme was worked out. The stability of solid solution was studied by determining the leaching concentration of arsenic by toxicity leaching experiment. The results are as follows: 1. Using Ca (NO_3) _ 24H _ 2O, (NH_4) _ 2HPO _ 4H _ 2O, (NH_4) _ 2HPO _ 4N _ 3AsO _ 4 12H_2O and Si (OCH_2CH_3) _ 4 as raw materials, different arsenic hydroxyapatite (As-HA) and modified arsenic-silico-hydroxyapatite (As-Si-HA) were successfully prepared by hydrothermal method. The optimum reaction conditions were obtained as follows: hydrothermal reaction temperature was 200 鈩，
本文编号：2291645
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