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811.
812.
Pavlović J Stopić S Friedrich B Kamberović Z 《Environmental science and pollution research international》2007,14(7):518-522
Goal, Scope and Background This paper is a part of the research work on ‘Integrated treatment of industrial wastes towards prevention of regional water
resources contamination — INTREAT’ the project. It addresses the environmental pollution problems associated with solid and
liquid waste/effluents produced by sulfide ore mining and metallurgical activities in the Copper Mining and Smelting Complex
Bor (RTB-BOR), Serbia. However, since the minimum solubility for the different metals usually found in the polluted water
occurs at different pH values and the hydroxide precipitates are amphoteric in nature, selective removal of mixed metals could
be achieved as the multiple stage precipitation. For this reason, acid mine water had to be treated in multiple stages in
a continuous precipitation system-cascade line reactor.
Materials and Methods All experiments were performed using synthetic metal-bearing effluent with chemical a composition similar to the effluent
from open pit, Copper Mining and Smelting Complex Bor (RTB-BOR). That effluent is characterized by low pH (1.78) due to the
content of sulfuric acid and heavy metals, such as Cu, Fe, Ni, Mn, Zn with concentrations of 76.680, 26.130, 0.113, 11.490,
1.020 mg/dm3, respectively. The cascade line reactor is equipped with the following components: for feeding of effluents, for injection
of the precipitation agent, for pH measurements and control, and for removal of the process gases. The precipitation agent
was 1M NaOH. In each of the three reactors, a changing of pH and temperature was observed. In order to verify efficiency of
heavy metals removal, chemical analyses of samples taken at different pH was done using AES-ICP.
Results Consumption of NaOH in reactors was 370 cm3, 40 cm3 and 80 cm3, respectively. Total time of the experiment was 4 h including feeding of the first reactor. The time necessary to achieve
the defined pH value was 25 min for the first reactor and 13 min for both second and third reactors. Taking into account the
complete process in the cascade line reactor, the difference between maximum and minimum temperature was as low as 6°C. The
quantity of solid residue in reactors respectively was 0.62 g, 2.05 g and 3.91 g. In the case of copper, minimum achieved
concentration was 0.62 mg/dm3 at pH = 10.4. At pH = 4.50 content of iron has rapidly decreased to < 0.1 mg/dm3 and maintained constant at all higher pH values. That means that precipitation has already ended at pH=4.5 and maximum efficiency
of iron removal was 99.53%. The concentration of manganese was minimum at pH value of 11.0. Minimum obtained concentration
of Zn was 2.18 mg/dm3 at a pH value of 11. If pH value is higher than 11, Zn can be re-dissolved. The maximum efficiency of Ni removal reached
76.30% at a pH value of 10.4.
Discussion Obtained results show that efficiency of copper, iron and manganese removal is very satisfactory (higher than 90%). The obtained
efficiency of Zn and Ni removal is lower (72.30% and 76.31%, respectively). The treated effluent met discharge water standard
according to The Council Directive 76/464/EEC on pollution caused by certain dangerous substances into the aquatic environment
of the Community. Maximum changing of temperature during the whole process was 6°C.
Conclusion This technology, which was based on inducing chemical precipitation of heavy metals is viable for selective removal of heavy
metals from metal-bearing effluents in three reactor systems in a cascade line.
Recommendations and Perspectives The worldwide increasing concern for the environment and guidelines regarding effluent discharge make their treatment necessary
for safe discharge in water receivers. In the case where the effluents contain valuable metals, there is also an additional
economic interest to recover these metals and to recycle them as secondary raw materials in different production routes.
ESS-Submission Editor: PhD Hailong Wang, hailong.wang@ensisjv.com 相似文献
813.
Xinwan Zhang Guangyuan Meng Jinwen Hu Wanzi Xiao Tong Li Lehua Zhang Peng Chen 《Frontiers of Environmental Science & Engineering》2023,17(8):97
814.
815.
Bi_2MoO_6薄膜电极光电催化氧化处理氰化物的研究 总被引:1,自引:0,他引:1
本文采用非晶态配合物法及浸渍提拉法在导电玻璃基底上制备了Bi2MoO6薄膜电极,采用此电极在可见光(λ420 nm)照射下进行了光电催化氧化处理氰化物的研究.通过场发射扫描电子显微镜和X射线衍射对电极的晶体结构进行了表征,发现导电玻璃基底上充分而平均地覆盖着黄色的纳米Bi2MoO6颗粒,形成了γ-Bi2MoO6相.在Bi2MoO6电极处理络合态氰化物Cu(CN)2-3实验中,总氰化物的去除率和Cu的回收率大致是随着电压的升高而增大,当电压为2.0 V,反应时间为120 min时,处理效果最好,剩余总氰化物和Cu的含量分别为30%和35%.破络合后的Cu2+一部分以Cu(Ⅱ)形式沉积在阳极上,一部分转化为Cu单质沉积在阴极上.在Bi2MoO6电极处理自由态氰化物NaCN实验中,总氰化物的去除率大致也是随着电压的升高而增大,当电压为2.0 V,反应时间为120 min时,剩余总氰化物含量为5%. 相似文献
816.
谢向东 《辽宁城乡环境科技》2013,(6):62-64
建立了用离子选择电极测定粉煤灰中氟含量的方法,用硝酸钾—柠檬酸钠作为离子强度调节剂,并采用碱熔法处理样品,测定结果的相对标准偏差为1.55%~2.06%,回收率93.89%~98.35%,表明方法的准确度较高,可用于粉煤灰样品中氟的简单分析。 相似文献
817.
TiO2纳米孔阵列光催化废水燃料电池的性能研究 总被引:1,自引:0,他引:1
以模拟有机废水和实际有机废水为研究对象,以TiO2纳米孔阵列电极作光阳极,金属铂黑做阴极,设计了一种光催化废水燃料电池(PFC),用于有机废水处理和废水有机物化学能的综合利用.论文考查了不同实验条件下组成的电池体系的性能,表明基于TiO2纳米孔阵列光阳极的光催化废水燃料电池既能处理废水又能够表现出良好的电池性能,如以0.05mol/L乙酸为底物的光催化废水燃料电池,其开路电压1.16V,短路电流1.28mA/cm2,最大输出功率密度0.28mW/cm2. 相似文献
818.
This study introduced TiO2-pillared clays (TiO2-PILC) as a support for the catalytic oxidation of NO and analyzed the performance of chromium oxides as the active site of the oxidation process. Cr-based catalysts were prepared by a wet impregnation method. It was found that the 10 wt.% chromium doping on the support achieved the best catalytic activity. At 350℃, the NO conversion was 61% under conditions of GHSV = 23600 hr^-l. The BET data showed that the support particles had a mesoporous structure. Hz-TPR showed that Cr(10)TiP (10 wt.% Cr doping on TiO2-PILC) clearly exhibited a smooth single peak. EPR and XPS were used to elucidate the oxidation process. During the NO + O2 adsorption, the intensity of evolution of superoxide ions (O2^-) increased. The content of Cr^3+ on the surface of the used catalyst was 40.37%, but when the used catalyst continued adsorbing NO, the Cr^3+ increased to 50.28%. Additionally, Oα/Oβ increased markedly through the oxidation process. The NO conversion decreased when SO2 was added into the system, but when the SO2 was removed, the catalytic activity recovered almost up to the initial level. FT-IR spectra did not show a distinct characteristic peak of SO4^2-. 相似文献
819.
为研究电化学技术对硝酸盐氮的去除作用,本实验以TiO2纳米管(TiO2-NT)为基体,利用电沉积法制备了Bi-TiO2纳米管阵列电极(Bi-TNA).同时,采用X-射线衍射仪(XRD)、扫描电子显微镜(SEM)对电极涂层表面形貌和晶体结构进行表征,并分析了电流密度、pH、初始浓度对硝态氮去除、亚硝态氮和氨氮转换、总氮去除及氮气选择性的影响.最后分析了Bi-TNA电极对硝态氮去除的动力学模型.结果表明,在单因素水平下,最佳操作条件为:硝态氮浓度为50 mg·L-1,电流密度为30 mA·cm-2,pH值为8.5.Bi-TNA电极对硝态氮的还原过程都遵循一级反应动力学. 相似文献
820.
随着水泥窑脱硝技术从理论探讨走向实际应用,水泥生产企业在NOx减排方案的选择上,需综合考虑区域特点、炉型特性和长远环保要求,采用专业的调研检测、个性化方案设计和周全的工程实施,以有利企业发展和满足环保要求。 相似文献