Zhu Yinian

The Effects of Different Anaerobic Fermentation Temperature on Biogas Fermentation of Swine Manure

Biogas yields and methane productivity were studied at different temperatures (15¡æ, 20¡æ, 25¡æ, 30¡æ and 35¡æ) by the way of anaerobic fermentation experiment which takes wine manure as biogas fermentation raw material, and take the sediment from rural methane fermentation as inoculate matter. The results indicated that temperature affected the material consumption time, the higher temperature, the faster material consumption, and then, fermentation period was become shorter too. However, more gaseous impurities were produced when anaerobic fermentation temperature increased relatively. Temperature of anaerobic fermentation had a great influence on methane production. Low temperature goes against the production of methane. Biogas yield and methane yield can ascend to the peak quickly at high anaerobic fermentation temperature. Taking into account production efficiency and the quality of digestion, temperature condition of 30 and fermentation period of 31d ¡æ in swine manure anaerobic fermentation are suitable for large scale farms.

Gneiss-Water interaction and water evolution during the early stages of dissolution experiments at room temperature

Gneiss-distilled water interaction at room temperature was investigated with batch-reactors to study water-rock reaction and geochemical evolution of the aqueous phase with time. The ion concentrations in water were controlled not only by the dissolution of primary minerals, but also by the precipitation of secondary minerals. The decreasing fraction sizes of gneiss could favor dissolution and precipitation simultaneously. Ca2+ and K+ were the major cations, and HCO3− was the major anion in water. All the ions except Ca2+ increased in concentration with time. The Ca2+ release from the rock to the aqueous phase was initially much faster than the release of K+, Na+ and Mg2+. But after about 5–24 hours, the Ca2+ concentrations in water decreased very slowly with time and became relatively stable. During the experiment, the water varied from the Ca-(K)-HCO3-type water to the K-Ca-HCO3-type water, and then to the K-(Ca, Na)-HCO3-type water. The water-gneiss interaction was dominated by the dissolution of K-feldspar in the solution. The remaining secondary minerals were mainly kaolinite, illite and K (Mg)-mica.

羟基磷灰石/蔗渣炭复合吸附剂的制备及其对As(V)的吸附机理

以甘蔗渣为原料，采用水热合成法制备羟基磷灰石/蔗渣炭复合吸附剂--HBA，通过静态吸附试验研究HBA对As（Ⅴ）的吸附特性，并采用红外光谱和X射线光电子能谱对吸附前后的HBA进行表征，探讨其吸附As（Ⅴ）的机理.结果表明：HBA的比表面积为89.52 m2/g，pHzpc（零点电荷）=7.2，HBA上的羟基磷灰石的分子式为Ca10（PO4）6（OH）2.HBA吸附As（Ⅴ）的效果最佳pH为5.0~9.0.Langmuir等温吸附模型适合拟合HBA对As（V）的吸附等温线，25℃时Langmuir最大吸附量为6.76 mg/g，是蔗渣炭对As（Ⅴ）最大吸附量的20多倍.红外光谱分析表明，HBA含有的＝C＝O、─OH、─COOH等含氧官能团，可为化学吸附提供充足的吸附位点和提高HBA的吸附能力.XPS分析表明，HBA表面的含氧官能团[如羧基（─O─C＝O，532.2 eV）、羟基（─OH，530.6 eV）]参与了吸附反应，羟基磷灰石能提高HBA吸附As（Ⅴ）的能力，被吸附到HBA表面上的As主要以AsO43-和HAsO42-形态存在.

The influence of impurities on the dissolution of Ca- and Sr-bearing barite at room temperature

The reaction path in the (Ba, Sr, Ca) SO4 solid-solution aqueous-solution (SSAS) system was experimentally studied using a batch-reactor method. The effect of the impurities “fluorite” and “iron sulfides” admixed in a natural barite sample on the reaction path was followed by analyzing the aqueous solution continuously. The dissolution and precipitation of the impurity “fluorite” affected strongly the reaction path in the SSAS system, especially the Ca/Sr/Ba ratio in the aqueous solution. This influence became stronger with decreasing CaSO4 in the solid solution. The dissolution and precipitation of fluorite could hinder the CaSO4 component from dissolving into water, and reduce the release rate of SO 4 2− from the solid solution to the aqueous solution and the removing rate of Ba2+ from the aqueous solution. In the presence of fluorite and sulfides, the aqueous Ba2+ and Sr2+ concentrations were controlled by the dissolution-precipitation of the end-members BaSO4 and SrSO4, respectively; the aqueous F−, Ca2+ and SO 4 2− concentrations were controlled by the dissolution-precipitation of fluorite. The incongruent dissolution of the (Ba, Sr, Ca) SO4 solid solution caused the solid phase to become progressively more enriched in the more insoluble component (BaSO4), while the aqueous composition shifted towards the more soluble end-members (SrSO4 and CaSO4) as equilibrium was approached to.The reaction path in the (Ba, Sr, Ca) SO4 solid-solution aqueous-solution (SSAS) system was experimentally studied using a batch-reactor method. The effect of the impurities “fluorite” and “iron sulfides” admixed in a natural barite sample on the reaction path was followed by analyzing the aqueous solution continuously. The dissolution and precipitation of the impurity “fluorite” affected strongly the reaction path in the SSAS system, especially the Ca/Sr/Ba ratio in the aqueous solution. This influence became stronger with decreasing CaSO4 in the solid solution. The dissolution and precipitation of fluorite could hinder the CaSO4 component from dissolving into water, and reduce the release rate of SO42− from the solid solution to the aqueous solution and the removing rate of Ba2+ from the aqueous solution. In the presence of fluorite and sulfides, the aqueous Ba2+ and Sr2+ concentrations were controlled by the dissolution-precipitation of the end-members BaSO4 and SrSO4, respectively; the aqueous F−, Ca2+ and SO42− concentrations were controlled by the dissolution-precipitation of fluorite. The incongruent dissolution of the (Ba, Sr, Ca) SO4 solid solution caused the solid phase to become progressively more enriched in the more insoluble component (BaSO4), while the aqueous composition shifted towards the more soluble end-members (SrSO4 and CaSO4) as equilibrium was approached to.