【摘要】 以一种新型碳基材料——氧化石墨烯(GO)为吸附剂,以乌梁素海表层沉积物中重金属Cu为研究对象,考察了GO投加量、沉积物pH值、有机质种类及其质量分数在35 d老化时间内对Cu稳定固化效果的影响。实验中利用电位法测定沉积物的pH值和氧化还原电位值(ORP),通过BCR连续提取法分析Cu各形态含量的分布。研究结果表明,随着GO投加量(2%、4%、6%、8%和10%)的增加,GO可以有效地将Cu从不稳定状态转化为稳定状态。在质量分数为10%时,Cu的酸可提取态较原始状态减少3.76%,残渣态增加28.16%。另外在不同pH(6、7、8和9)下,GO对Cu的稳定效果不同,表现出pH=9>pH=8>pH=7>pH=6的递减关系;并且当pH=9时,沉积物的ORP值在整个老化时间内最低。选用腐殖酸(HA)和富里酸(FA)两种有机质研究其对GO稳定沉积物中Cu的影响。结果发现,加入HA和FA后,GO对沉积物中Cu的稳定效果明显提高,且随着HA和FA质量分数(1%、5%、10%和15%)的增加而增加,当质量分数为15%时固定效果最好。GO+15%HA使重金属Cu的残渣态增加了34.95%,GO+15%FA使重金属Cu残渣态增加了32.96%。以上实验数据表明,GO可以有效地将沉积物中Cu从不稳定态转化为稳定合态,降低沉积物中Cu向上覆水释放的风险。该研究围绕乌梁素海上覆水环境开展实验,以期望对高寒地区重金属污染沉积物的修复提供一种新的思路。更多还原

【Abstract】 In recent years, river sediments had been polluting by heavy metals due to large amounts of industrial wastewater, the migration and bioavailability of heavy metals in sediments adversely affect ecosystem health. In order to reduce the harm of heavy metals to the environment, a new carbon-based material, graphene oxide(GO), was used as an adsorbent to study stable curing of the heavy metal Cu in the surface sediments of Wuliangsuhai. The dosage of GO, pH value of sediment, organic matter type(HA or FA)and percentages were investigated to determine their effects for Stabilization of Cu on 35 days aging period. In the experiment, the pH value and Oxidation reduction potential(ORP) of the sediment were determined using potentiometry. The percentages of acid-soluble, reducible, oxidizable and residual Cu were analyzed by BCR continuous extraction method. The dosage of GO increased from 2% to 10% and unstable Cu was successfully transformed into stable Cu. For example, the percentages of the acid-soluble Cu decreased by 3.76% and the residual Cu increased by 28.16%. Furthermore, the stabilization of Cu varied with pH value, the large pH value is, the more stable Cu can be gained when pH value was 9, the ORP of the sediment was the lowest. Humic acid(HA) and fulvic acid(FA) were chosen to be added with GO, and it is found that the stablization of Cu became better with more HA or FA addition. And when the percentages of HA and FA were both 15%, the residual Cu increased by 34.95% and 32.96%,respectively. The results of this study indicated that GO can effectively transform unstable Cu into stable Cu, and can reduce the risk of Cu in the sediment releasing into surfacing water. The paper presents a new view for the restoration of heavy metal contaminated sediment in alpine regions.更多还原