EGI OpenIR
应用改性生物炭修复尾矿淋滤液汞砷污染
Alternative TitleTreatment of Hg and As pollution of tailing filtrate by modified biochar
迪力夏提·阿不力孜
Subtype博士
Thesis Advisor潘响亮
2020-06-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline理学博士
Keyword生物炭 铁氧化物 锰氧化物 汞砷污染 吸附 Biochar Iron Oxide Manganese Oxide Mercury and Arsenic Pollution Adsorption
Abstract本论文以棉花秸秆生物炭为原料,通过化学和生物学合成的方法制备了具有较高汞和砷吸附能力的铁/锰氧化物与生物炭的复合吸附剂。通过批量吸附实验对其吸附 As(III)和 Hg(II)的性能进行了评价,并考察了溶液 pH、金属离子浓度、吸附时间、离子强度、腐植酸、盐度等天然环境因子对 As(III)和 Hg(II)离子在铁/锰氧化物-生物炭复合吸附剂表面吸附的影响,进而阐明砷和汞吸附剂表面的吸附机制。另外,利用铁/锰氧化菌的作用原位合成生物源 Mn(II)/Fe(II)氧化物与生物炭复合物,评价其在模拟污水中同步修复砷和汞污染的可行性。最后将砷吸附能力较强的针铁矿/生物炭复合材料作为材料构建 PRB 柱,对模拟污水中砷和汞污染进行修复,考察改性生物炭在实际环境重金属污染水体的修复潜能。论文主要得到了以下结论:( 1)通过化学改性合成了锰氧化物负载的生物炭。 BET、 XRD、 FTIR、SEM-EDS、 Zeta 点位等表征结果揭示,改性后 MnOx 成功加载到生物炭表面。而相对于原生物炭,其化学锰氧化物改性后的产物表面理化性质发生变化。比表面积有所下降。 生物炭在改性前后的 Zeta 电位的均呈现电负性,表明两种生物炭的表面都带负电荷。吸附实验结果表明, 溶液 pH 值的变化对改性和非改性生物炭对 As(III)和 Hg(II)吸附产生显着影响, MnOx 改性后的产物能较好的从水溶液里去除 As(III)和 Hg(II)离子,特别是 MnOx 改性能提高生物炭吸附 As(III) 的能力(qm=102.4 mg/g)。吸附过程符合 Langmuir 模型( R2 均超过 0.98)。( 2)在不同原料配比、酸碱度、老化时间和温度下,通过 Fe(NO3)3·9H2O沉淀合成了不同的针铁矿/生物炭复合物。根据 SEM-EDS、 FTIR、 XRD、 Zeta点位等分析结果,不同条件下制备的针铁矿/生物炭复合材料表面各类元素种类大致相同,而其重量百分比存在一定差异。通过吸附实验确定, 生物炭和Fe(NO3)3·9H2O 质量比为 1:6、酸碱度为 pH=12、陈化温度 60℃以及陈化时间 60h为制备生物炭/针铁矿复合吸附材料的最佳条件。( 3) FTIR, XRD, SEM-EDS 分析证明,合成产物中针铁矿成功负载到生物炭表面。 BET 表明,针铁矿负载后生物炭比表面积从 12.681 m2/g 升高至 136.303m2/g。通过吸附实验发现, As(III)吸附量取决于溶液初始 pH 和金属离子初始浓度。当溶液初始 pH=3.0, As(III)吸附效果最好。离子强度和腐植酸的存在对针铁矿生物炭复合物的 As(III)的吸附性能起抑制作用。盐度变化有利于 As(III)在针铁矿/生物炭复合物表面的吸附。解吸实验证明, As(III)在离子强度、盐度、 EPS 的因子作用下从吸附剂表面解吸,其解吸量和解吸率跟各种环境因子浓度有一定的关系。等温吸附数据符合 Freundlich 和 Langmuir 等温线,吸附动力学数据符合准二级吸附模型( R2 大于 0.99)。( 4)锰氧化菌 MnB1 的作用下合成了生物源氧化锰与生物炭的复合物。 Zeta电位测试表明,合成的复合物 pH 在 3.0~10.0 均带负电荷。 SEM 和 XRD 测定结果表明,复合物表面元素 O 和 Mn 的信号证明锰氧化物的存在。根据模拟污染环境中对 Hg(II)和 As(III)同步去除实验结果, 在不同初始重金属浓度下, 微生物氧化生成的锰氧化物与生物炭的沉积物可从汞和砷污染水体中有效去除 As(III)和Hg(II),其吸附性能由反应体系中生物炭颗粒、二价锰浓度以及微生物锰氧化能力决定。( 5)利用厌氧亚铁氧化菌 PXL1 的作用,在不同浓度汞和砷污染环境中将菌株 PXL1 与一定量的生物炭共培养,培养 7 天后收集培养体系中生成的沉积物。通过 SEM-EDS、 XRD 和 FTIR 分析结果进一步说明了沉积物中生物源铁氧化物的存在。沉积物在不同初始 As(III)对其显示一定的修复性能, Fe(II)的含量、菌株 PXL1 的氧化作用在 As(III)的修复中起关键作用。亚铁被菌株 PXL1 氧化生成的铁氧化物能提高生物炭的 As(III)吸附性能。吸附实验结束后沉积物 SEM-EDS分析结果进一步证明 As(III)的吸附行为。( 6)以改性生物炭为介质构建了 PRB 柱子,用来修复模拟环境下汞砷污染修。汞砷污染水体修复实验表明, PRB 介质中针铁矿改性生物炭比例越高,其 As(III)修复效果越好,进行 120 h 后最大去除率达到 100%;纯生物炭含量越高,系统对 Hg(II)的去除率越大 99.99%。中性环境(初始 pH 为 6.0 左右)下以针铁矿生物炭复合材料为介质的 PRB 柱 As(III)和 Hg(II)去除效果最好。重金属初始浓度在 5.0~10.0 mg/L 时,其对 As(III)和 Hg(II)平均去除率均超过 99%。
Other AbstractIn this paper, iron/manganese oxide and biochar composite with high mercury andarsenic adsorption capacity was prepared from cotton stalk biochar through chemicaland biological synthesis as an adsorbent. As (III) and Hg (II) remediationperformances were conducted through batch adsorption experiments. The effects ofsolution pH, metal ion concentration, adsorption time, ionic strength, humic acid,salinity and other natural environmental factors were analyzed and adsorptionmechanism of As (III) and Hg (II) sorption on the adsorbet surface were clarified. Inaddition, biogenic Mn (II) /Fe (II) oxide and biochar composites were synthesized insitu by using iron/manganese oxidizing bacteria, and the feasibility of simultaneousremediation of arsenic and mercury contamination in simulated sewage was evaluated.Finally, the PRB column of goethite/biochar composite with strong arsenic adsorptioncapacity was built to repair arsenic and mercury pollution in simulated sewage, and toinvestigate the potential of modified biochar to repair heavy metals polluted water inthe actual polluted environment. The main conclusions of this paper are as follows:(1) The biochar loaded with manganese oxide was synthesized by chemicalmodification technology. The results of BET, XRD, FTIR, SEM-EDS and Zetapotential revealed that MnOx was successfully loaded onto the surface of biochar aftermodification.Compared with the original biochar samples, surface physicochemicalproperties of the products modified by loading chemical manganese oxides havechanged and the surface area has decreased. Zeta potential of the biochar before andafter modification showed electro negativity, indicating that the surface of both kindof biochar was negatively charged. The results of adsorption experiment showed thatsolution pH have significant effects on As (III) and Hg (II) adsorption. The modifiedproducts could remove more As (III) ions from aqueous solution (qm=102.4 mg/g).The adsorption isotherm fitted well to the Langmuir model, with R2 of more than0.98.(2) Fe(NO3)3·9H2O precipitation was used to synthesize goethite loaded biochar underdifferent condition, which include different raw material ratio, different pH, differentaging time and temperature. According to the results of SEM-EDS, FTIR, XRD andZeta potential analysis, main elements on the surface of goethite/biochar compositefron different synthesize condition are almost the same, but their weight percentages are different. It is confirmed through batch adsorption experiments that mass ratio ofbiochar and Fe(NO3)3·9H2O was 1:6, pH value was 12.0, aging temperature was 60℃and aging time 60h were the best condition to prepare biochar/goethite composite asadsorption material for As (III) and Hg (II) removal.(3) FTIR, XRD, and SEM-EDS analysis showed that goethite was successfully loadedto the surface of biochar from the synthetic product(GBC). BET showed that thespecific surface area of GBC increased from 12.681 m2/g to 136.303 m2/g after theloading of goethite. The adsorption capacity of As (III) depends on the initial pH ofthe solution and the initial concentration of metal ions. Initial pH of 3.0 achievedmaximum sorption capacity on As (III) by GBC. The presence of ionic strength andhumic acid inhibits the adsorption properties of As (III) in GBC. The change ofsalinity is beneficial to the adsorption of As (III) on the surface of adsorbents.Desorption experiments showed that changes in contents of ionic strength, EPS andsalinity could release some As (III) ion sorbed on the adsorbent surface, and thedesorption rate have a certain relationship with the concentration of variousenvironmental factors. The isothermal adsorption data fitted well to the Freundlichand Langmuir isotherms, and the adsorption kinetic data were in accordance withpseudo second-order model (R2>0.99).(4) The complex of biogenic manganese oxide and biochar was synthesized under therole of manganese oxidizing bacteria MnB1. The Zeta potential test showed that thecomposite was negatively charged at pH=3.0~10.0. The results of SEM and XRDshowed that the signal of O and Mn on the surface of the complex showed thepresence of manganese oxide. Based on the experimental results of simultaneousremoval of Hg(II) and As(III) from arsenic and mercury contaminated water atdifferent initial concentrations, sediments produced by microbial oxidation andbiochar can effectively remove As(III) and Hg(II) from mercury and arsenic pollutedwater, the sorption amount by sediments in the reaction system of two particles, werecontrolled by concentration of two valent manganese and by oxidation ability ofmicrobial manganese.(5) The anaerobic Fe(II) oxidizing bacteria PXL1 was used to produce biochar andbiogenic iron oxide complex by co culturing the strain PXL1 with a certain amount ofbiochar. Removal efficiency was tested in different concentrations of Hg and Ascontaminated water. After 7 days of cultivation, the sediment produced in the culture system was collected. The analysis of SEM-EDS, XRD and FTIR further illustratesthe existence of biogenic iron oxides in the sediments, which showed certain repairingproperties to arsenic at different initial As (III) concentration.The content of Fe (II)and PXL1 oxidation played a key role in the removal of As (III) pollution. Iron oxideproduced by the oxidation of strain PXL1 can improve the adsorption properties of As(III) of biochar. The adsorption behavior of As (III) was further confirmed by theSEM-EDS analysis of the sediment after the adsorption experiment.(6) The modified biochar was used as the medium to built PRB column, and used forremediation of mercury and arsenic pollution. It was found that the higher theproportion of goethite modified biochar in PRB medium, the better the As (III)remediation effect was. The maximum removal rate reached 100% after 120h. Thehigher the pure biochar content, the greater the removal rate of Hg (II), which reached99.99%. In neutral environment, the removal of As (III) and Hg (II) in PRB columnwith goethite modified biochar is the best. When the initial concentration of heavymetals was ranged from 5.0~10.0 mg/L, the average removal rates of As (III) and Hg(II) were more than 99%.
Subject Area生态学
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/15413
Collection中国科学院新疆生态与地理研究所
研究系统
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
迪力夏提·阿不力孜. 应用改性生物炭修复尾矿淋滤液汞砷污染[D]. 北京. 中国科学院大学,2020.
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