Competitive Complexation of Copper and Zinc by Sequentially Extracted Humic Substances from Manure Compost

Chicken manure with similar content of copper and zinc was changes of organic carbon and humus substance complexed chosen to conduct a composting experiment to investigate the copper （HS-Cu） and zinc （HS-Zn）, which were extracted by water （H2O）, sodium hydroxide （NaOH）, and sodium pyrophate-NaOH mixture （Na4P2O7-NaOH）, sequentially. Distributions of copper and zinc in fulvic acids （FA） and humic acids （HA） in the three extracts were studied. During manure composting, the concentrations of copper and zinc increased from about 500 mg kg^-1 in the raw material to 1 100 mg kg^-1 in the final products. HS-Cu in H2O, NaOH, and Na4P2O7-NaOH extracts occupied 6.7, 26.7, and 19% averagely of total copper and HS-Zn represented 2.7, 13.7, and 17% averagely of total zinc in compost, respectively. In water extracts, both HA and FA mainly complexed with Cu and the mole ratio of Cu to Zn was 2.8 in HA fractions and was 2.6 in FA fractions, respectively. HA mainly complexed with copper, so that the ratios of HA-Cu to HA-Zn averaged 3.4 in NaOH extracts. FA had a similar potential to complex with copper and zinc, so that the ratio of FA-Cu to FA-Zn was close to 1. In Na4P2O7-NaOH extracts, HA or FA had a similar potential to complex with copper and zinc. The ratio of HS-Cu to HS-Zn was close to 1. With manure composting, Na4P2O7-NaOH extractable HS-Zn increased to a level as high as HS-Cu. This indicated that more and more stable complexes of HS-Zn were formed in the late decomposition period. The competition between copper and zinc to be complexed with humic substance became weaker and weaker with the decomposition process.

曝气池活性污泥胞外聚合物对Pb^(2+)、Zn^(2+)、Cu^(2+)的吸附研究

[目的]研究曝气池活性污泥胞外聚合物对Pb2+、Zn2+、Cu2+的吸附能力。[方法]以曝气池活性污泥提取的胞外聚合物(EPS)作为吸附剂,研究了吸附时间、pH、EPS投加量、不同初始金属浓度以及Pb2+、Zn2+、Cu2+3种金属离子共存等因素对其吸附Pb2+、Zn2+、Cu2+的规律。[结果]吸附时间对EPS吸附Pb2+、Zn2+、Cu2+的影响均为随着时间的延长,去除率不断增加,分别在30、60和20 min处达到吸附平衡。pH对其的影响均表现为在酸性条件下随着pH的上升,去除率先上升后又下降,当pH=6时,去除率均达最大,分别为52.17%、39.83%和65.45%,之后去除率均随pH的升高先下降后上升。随着EPS投加量增加,Pb2+的去除率先增大后降低,其吸附量呈逐渐下降的趋势;Zn2+的去除率和吸附量均逐渐减少,而Cu2+的去除率和吸附量均逐渐增加。随着初始金属离子浓度的增加,EPS对Pb2+、Zn2+、Cu2+的吸附量均逐渐增加,而去除率均逐渐减小。3种金属离子共存时,EPS对Pb2+的去除率随着EPS投加量的增加先增加后降低,Zn2+的去除率是逐渐降低的,Cu2+的去除率先降低后上升,当EPS投加量>17 ml后,Cu2+的去除率远远高于Pb2+和Zn2+。[结论]该研究为含重金属废水处理提供理论依据。

联合添加木质素多酚与铜锌交联物质对断奶仔猪生长性能、免疫力及铜锌沉积的影响

试验旨在研究日粮中联合添加木质素多酚和铜锌交联物质对断奶仔猪生长性能、免疫力和铜锌沉积的影响。选择体重相近、健康状况良好的“杜×长×大”三元杂交断奶仔猪96头,随机分成3组,每组4个重复,每个重复8头猪。对照组仔猪饲喂基础日粮+2 kg/t氧化锌+100 g/t金霉素+40 g/t黏杆菌素,T1组仔猪饲喂基础日粮+1 kg/t木质素多酚+700 g/t铜锌交联物质,T2组仔猪饲喂基础日粮+2 kg/t木质素多酚+700 g/t铜锌交联物质。预试期7 d,正式试验期28 d。结果显示,与对照组相比,T2组仔猪平均日采食量和平均日增重均略有提高(P>0.05),T1组仔猪平均日采食量显著降低(P<0.05)。各组间仔猪的料重比和腹泻率均无显著差异(P>0.05)。与对照组相比,T1组仔猪血清中干扰素-γ (IFN-γ)含量显著降低(P<0.05)。与对照组和T1组相比,T2组仔猪血清的补体C4含量升高,且显著高于T1组(P<0.05);T2组仔猪血清的D-乳酸(DLA)含量降低,且显著低于T1组(P<0.05)。与对照组相比,T1组和T2组仔猪的血清和粪便中锌含量均显著降低(P<0.05)。研究表明,在断奶仔猪日粮中联合添加2 kg/t木质素多酚和700 g/t铜锌交联物质替代高锌与抗生素组合,能够保持断奶仔猪正常的生长性能,提高免疫力,显著降低粪便中锌的排泄量。