Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell （PAC） was used for...Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell （PAC） was used for the removal of Pb^2＋ from aqueous solution. The impacts of the Pb25 adsorption capacities of the acid-modified carbons oxidized with HNO3 were also investigated. The surface functional groups of PAC were confirmed by Fourier transform infrared （FTIR） spectroscopy, X-ray photoelectron spectroscopy （XPS）, Boehm titration. The textural properties （surface area, total pore volume） were evaluated from the nitrogen adsorption isotherm at 77 K. The experimental results presented indicated that the adsorption data fitted better with the Langmuir adsorption model. A comparative study with a commercial granular activated carbon （GAC） showed that PAC was 10.3 times more efficient compared to GAC based on Langmuir maximum adsorption capacity. Further analysis results by the Langmuir equation showed that HNO3 [20% （by mass）] modified PAC has larger adsorption capacity of Pb^2＋ from aqueous solution （as much as 35.5 mg·g^-1）. The adsorption capacity enhancement ascribed to pore widening, increased cation-exchange capacity by oxygen groups, and the promoted hydrophilicity of the carbon surface.展开更多
开发了酸性无氰镀镉新工艺NCC-617。镀液组成为：氯化镉35-40 g/L,配位剂120-160 g/L,氯化钾140-180 g/L,光亮剂1.5-2.5 m L/L,辅助剂25-35 m L/L,p H 6.0-7.0。工艺条件为：挂镀──温度15-35℃,阴极电流密度0.5-1.5 A/dm^2;滚镀温度15...开发了酸性无氰镀镉新工艺NCC-617。镀液组成为：氯化镉35-40 g/L,配位剂120-160 g/L,氯化钾140-180 g/L,光亮剂1.5-2.5 m L/L,辅助剂25-35 m L/L,p H 6.0-7.0。工艺条件为：挂镀──温度15-35℃,阴极电流密度0.5-1.5 A/dm^2;滚镀温度15-30℃,槽电压4-7 V,滚筒转速3-5 r/min。在电流密度1 A/dm2下,镉的沉积速率为0.33μm/min。NCC-617镀液的电流效率为73%,均镀能力为41%-52%,深镀能力为9.2。镀镉层经低铬彩色钝化后中性盐雾试验2 000 h仍无白锈生成,其耐蚀性实现了重大突破。镀层的氢脆性和结合力合格。总之,NCC-617镀镉工艺具有镀液稳定,镀层性能优良,电镀废水容易处理的优点,具有较好的应用前景。展开更多
利用硝酸对颗粒活性炭进行改性,处理含铬废水,并考察了吸附时间、溶液pH、吸附剂加入量对改性活性炭吸附Cr(Ⅵ)效果的影响。实验结果表明:经过硝酸氧化改性的活性炭比表面积有所增加,官能团总量增加明显;吸附剂对Cr(Ⅵ)的去除率随振荡...利用硝酸对颗粒活性炭进行改性,处理含铬废水,并考察了吸附时间、溶液pH、吸附剂加入量对改性活性炭吸附Cr(Ⅵ)效果的影响。实验结果表明:经过硝酸氧化改性的活性炭比表面积有所增加,官能团总量增加明显;吸附剂对Cr(Ⅵ)的去除率随振荡时间的增加而增加;对于质量浓度为10 mg/L的100 mL Cr(Ⅵ)溶液,当溶液pH为中性,30%(体积分数)硝酸改性的颗粒活性炭的加入量为0.4 g,其对Cr(Ⅵ)的最大去除率为98%。展开更多
文摘Metal ion contamination of drinking water and waste water, especially with heavy metal ion such as lead, is a serious and ongoing problem. In this work, activated carbon prepared from peanut shell （PAC） was used for the removal of Pb^2＋ from aqueous solution. The impacts of the Pb25 adsorption capacities of the acid-modified carbons oxidized with HNO3 were also investigated. The surface functional groups of PAC were confirmed by Fourier transform infrared （FTIR） spectroscopy, X-ray photoelectron spectroscopy （XPS）, Boehm titration. The textural properties （surface area, total pore volume） were evaluated from the nitrogen adsorption isotherm at 77 K. The experimental results presented indicated that the adsorption data fitted better with the Langmuir adsorption model. A comparative study with a commercial granular activated carbon （GAC） showed that PAC was 10.3 times more efficient compared to GAC based on Langmuir maximum adsorption capacity. Further analysis results by the Langmuir equation showed that HNO3 [20% （by mass）] modified PAC has larger adsorption capacity of Pb^2＋ from aqueous solution （as much as 35.5 mg·g^-1）. The adsorption capacity enhancement ascribed to pore widening, increased cation-exchange capacity by oxygen groups, and the promoted hydrophilicity of the carbon surface.
文摘利用硝酸对颗粒活性炭进行改性,处理含铬废水,并考察了吸附时间、溶液pH、吸附剂加入量对改性活性炭吸附Cr(Ⅵ)效果的影响。实验结果表明:经过硝酸氧化改性的活性炭比表面积有所增加,官能团总量增加明显;吸附剂对Cr(Ⅵ)的去除率随振荡时间的增加而增加;对于质量浓度为10 mg/L的100 mL Cr(Ⅵ)溶液,当溶液pH为中性,30%(体积分数)硝酸改性的颗粒活性炭的加入量为0.4 g,其对Cr(Ⅵ)的最大去除率为98%。
