过氧化钙的制备与应用研究进展

综述了过氧化钙的制备与应用研究的最新进展.过氧化钙的制备方法有钙盐法、氧化钙法、氢氧化钙法、空气阴极法、喷雾法等.在制备过程中,为了提高双氧水的利用率和产物中过氧化钙的含量,常加入稳定剂.为了使过氧化钙的供氧更持久平缓,可制备包埋型过氧化钙.过氧化钙可用于水稻直播、食用菌生产、土壤改良、水产养殖、污水处理、化工生产与空气净化等领域,可用作食品和饲料添加剂、水果和蔬菜保鲜剂、氰化法提金助剂等,有着越来越广泛的用途.     

过氧化钙的制备与应用研究进展

综述了过氧化钙的制备与应用研究的最新进展。过氧化钙的制备方法有钙盐法、氧化钙法、氢氧化钙法、空气阴极法、喷雾法等。在制备过程中,为了提高双氧水的利用率和产物中过氧化钙的含量,常加入稳定剂。为了使过氧化钙的供氧更持久平缓,可制备包埋型过氧化钙。过氧化钙可用于水稻直播、食用菌生产、土壤改良、水产养殖、污水处理、化工生产与空气净化等领域,可用作食品和饲料添加剂、水果和蔬菜保鲜剂、氰化法提金助剂等,有着越来越广泛的用途。     

过氧化钙的应用及其发展前景

本文叙述了过氧化钙在农业、水产养殖、废水处理、涂料、矿物加工、化学工业等方面的应用     

过氧化钙的应用

本文综述过氧化钙在农业种植、水产养殖、食品保鲜、医用药物、环境保护等方面的应用。     

“十二五”期间市场前景广阔的化工产品

＂十二五＂规划纲要中提出了要坚持把经济结构战略性调整作为加快转变经济发展方式的主攻方向、坚持把科技进步和创新作为加快转变经济发展方式的重要支撑、坚持把保障和改善民生作为加快转变经济发展方式的根本出发点和落脚点、坚持把建设资源节约型、环境友好型社会作为加快转变经济发展方式的重要着力点等要求,     

FMH—水稻育苗床土调节剂对水稻的增产效应

东北地区无霜期短,水稻旱育移栽技术的推广应用为水稻高产早熟提供了十分有效的途径。在水稻旱育苗过程中要进行调酸、施肥、消毒、灭草、通风等多个环节与步骤,操作起来较为复杂,不宜掌握。为此,急需解决一种变复杂作业为复合一体化作业的方式。根据这种需求,我们利用发电厂排出的粉煤灰作载体,研制出《FMH-水稻育苗床土调节剂》(以下简称 FMH-床土调节剂)以适应水稻旱育苗移栽技术的需要。粉     

微纳气泡技术及在农业种植与养殖方面的应用

微纳米气泡具有很多独特的性质,如超长寿命、表面带电、比表面积大和传质效率高等.由于这些独特性质,微纳米气泡在诸多领域表现出巨大的应用前景,如水处理、农业、清洗、生物医药、土壤改良等.文中重点介绍了微纳米气泡在农业、水产养殖业中的应用.首先,介绍了微纳米气泡的定义和特性;其次,对微纳米气泡在农业养殖方面的应用进行了简要综...     

过氧化钙常温生产新工艺研究

通过加入稳定剂开辟了在常温下生产过氧化钙的新途径。     

Ozone Versus Ozone/Peroxide Induced Particle Destabilization And Aggregation: A Pilot Study

This research compares the role of ozone and the conjunctive use of ozone plus hydrogen peroxide in particle destabilization and particle aggregation, and improvement in filtered water quality. Particle destabilization was observed at all doses of ozone and ozone/peroxide studied, whereas aggregation was observed with ozone only at lower doses (> 2 mg/L) and in conjunction with ozone/peroxide (all doses studied). As compared to alum alone, the ozone-plus-alum and ozone/peroxide-plus-alum treatments provided improved flocculation and better filtered water quality. In addition, each of these preoxidations significantly reduced alum requirements. Overall, in terms of particle destabilization and aggregation; i.e., effectiveness as a coagulation aid, Ozone/peroxide performed better than ozone.     

一种烧制钾钙肥助剂的研究

利用不溶性含钾岩石和石灰石为主要原料,适量添加硫酸钠作为反应助剂,经高温煅烧制备出钾钙肥。对助剂硫酸钠的加入量、烧结温度、烧结时间进行了研究,得到了烧制钾钙肥的优化条件。     

钠法漂粉精装置二次反应探讨

介绍了钠法漂粉精装置从一次母液中回收次氯酸钙的二次反应过程和参数,并对完善二次反应进行了讨论。     

Degradation Of Selected Herbicides In A Lowland Surface Water By Ozone And Ozone-Hydrogen Peroxide

The efficiency of ozone, and ozone in combination with hydrogen peroxide, for the degradation of five herbicides: Atrazine, Benazolin, Bentazone, Imazapyr and Triclopyr, under controlled laboratory conditions was investigated. Experiments were conducted at pH 7.5 in a bubble contactor column with a raw lowland surface water spiked with initial active ingredient concentrations of 2 μg/L. Mean consumed ozone doses were approximately 1, 2 and 3 mg O₃/L. Hydrogen peroxide was added simultaneously to the application of ozone in a series of six mass ratios, between 0.0 and 1.0, with each of the consumed ozone doses. The results demonstrated a greater but varying removal of all herbicides achieved with increasing consumed ozone and applied hydrogen peroxide doses.     

Calcium phosphate fouling on TiN-coated stainless steel surfaces: Role of ions and particles

Modifying the surface properties of the stainless steel used in heat exchangers to decrease its tendency for the building-up of milk deposits seems to be a promising strategy to reduce fouling during heat treatment in the dairy industry. In this work, several modified stainless steel surfaces, obtained by reactive magnetic sputtering, were used as fouling supports for a milk-simulating mineral solution under constant conditions of temperature, pH and calcium concentration. The aim of the work was to quantify deposition and removal parameters, based on the influence of surface energy properties on the type of deposit. The fouling process was characterized by the surface reaction coefficient of the ions present in solution, as well as the adhesion coefficients of the particles formed in the bulk. An insight on the mechanisms of deposition and removal processes was achieved, as well as by the dependence between those two processes and the electron-donor component (γ^-) of the surface energy of the stainless steel-based materials. The surfaces with lower γ^- were found to have lower amounts of deposit, and this deposit could be more easily cleaned than for the other surfaces (including the non-modified stainless steel).     

Oxidation of Aged Raw Landfill Leachate with O3 Only and O3/H2O2: Treatment Efficiency and Molecular Size Distribution Analysis

An aged raw landfill leachate was taken from the equalization storage tank at Clover Bar Landfill Leachate Treatment Plant, Edmonton, Alberta, Canada. The average quality parameters of this leachate were: COD=1,090mg/L, BOD₅=39mg/L, color=1,130 TCU, NH₃-N=455mgN/L, alkalinity=4,030mg/L as CaCO₃and pH=8.30. The major fraction of this leachate was large refractory organic compounds. Ozone (O₃) only and O₃ combined with hydrogen peroxide (O₃/H₂O₂) were applied to treat this leachate, aiming at enhancing COD and color reduction and increasing its biodegradability (i.e., the ratio of BOD₅/COD). All of the O₃ only and O₃/H₂O₂ oxidation experiments were performed in a gas washing bottle equipped with a fine bubble diffuser. The used ozone dose ranged from 1.2 to 12.5g O₃/L leachate for O₃ only treatment, and 1.8 to 13.8g O₃/L leachate for O₃/H₂O₂ treatment. H₂O₂ dose for O₃/H₂O₂ treatment was 0.63g H₂O₂/L leachate. COD, BOD₅, color, NH₃-N, nitrite+nitrate, and alkalinity were measured before and after treatment. Meanwhile the molecular size distribution of the leachate, before and after treatment, was analyzed by using a high-performance liquid chromatograph (HPLC) with gel filtration column and UV detector at 254nm. The addition of H₂O₂ had an insignificant effect (at 5% significance level) on enhancing COD and color reduction. After oxidation, the maximum BOD₅ increase was about 110% for O₃/H₂O₂ treatment and about 141% for O₃ only treatment at a used ozone dose of 3.6g O₃/L leachate and 2.6g O₃/L leachate for O₃/H₂O₂ and O₃ only, respectively. As the used ozone dose increased, NH₃-N and alkalinity decreased considerably, and nitrite+nitrate increased accordingly. Treatment efficiency models, which describe the changes in COD, BOD₅/COD, NH₃-N, nitrite+nitrate, and alkalinity as functions of the used ozone dose, were developed. Statistically (at 5% significance level), the treatment efficiency models for both treatments are not different. According to the results of molecular size distribution analysis, no correlation was observed between the BOD₅ increase and oxidation by-products’ formation.     

Calcium zirconate: preparation, properties and application to the solid oxide galvanic cells

Stoichiometric, and doped with a small amount of CaO, calcium zirconate dense samples were prepared. X-ray analysis revealed that the solid solution was formed in the concentration range up to x=0.06 in the {xCaO+(1−x)CaZrO₃} mixture. The activity of CaO in the solid solution was determined by the emf method at the temperatures 1073 and 1273 K. The electrical conductivity was measured using both dc four-probe and ac impedance spectroscopy methods. The maximum conductivity values were observed for the sample with x=0.06. This sample was used for further investigation. The oxygen-ion transference number, estimated by the emf method, appeared to be close to unity. The partial electronic (electron and electron hole) conductivities, deduced from current–potential curves following the polarisation method, were found to be very small with respect to total electrical conductivity. Then, the sample was tested as an electrolyte in solid oxide galvanic cells. In this way, the values of the standard free enthalpy of formation of cobalt and nickel silicates at the temperatures 1073 and 1273 K were determined and compared with those obtained by other authors.     

Slow sand filtration of UASB reactor effluent: A promising post treatment technique

The study was carried out to evaluate the feasibility of slow sand filtration as a promising post treatment method for the up-flow anaerobic sludge blanket (UASB) reactor effluent. Laboratory scale filter column of 10 cm diameter and 0.54 m sand media depth was used to study the process performance. It was found out that slow sand filtration with 0.43 mm effective sand size is the most effective at a filtration rate of 0.14 m/h. It is capable of removing 91.6% of turbidity, 89.1% of suspended solids (SS), 77% of chemical oxygen demand (COD) and 85% of bio-chemical oxygen demand (BOD), 99.95% of total and fecal coliforms (TC and FC) and 99.99% of fecal streptococci (FS). Slow sand filters efficiently reduce the mass of suspended material and extend the filter run for more time (7 days) at a hydraulic load of 0.14 m/h as compared to the hydraulic load of 0.19 m/h and 0.26 m/h. Therefore, due to excellent effluent quality, it can be said that slow sand filtration would be a promising technology for the post treatment of small-scale UASB reactor effluent in developing countries, where treated effluent can be reused for various recreational purposes i.e. gardening and irrigation, as well as for safe discharge.     

Fluidized bed drying of a pharmaceutical powder: A parametric investigation of drying of dibasic calcium phosphate

A parametric analysis of four fluidized bed dryer operating parameters—initial moisture content, material loading, heating air temperature, and air flux—was carried out using two factorial experimental designs. Two different dryer scales, the Glatt GPCG-1 and MiniGlatt, with chamber volumes of 23 and 3?L, respectively, were used to dry dibasic calcium phosphate powders. According to a Pareto analysis, initial moisture content and air flux were the most significant variables. For the larger GPCG-1, the four variables used in the factorial tests were found to be independent. For the smaller MiniGlatt, the interaction of the initial moisture content and the air flow rate was also significant. From the parametric analysis, it was observed that drying is dominated by the constant drying stage, and zero-order kinetics, for the mild drying conditions (appropriate for many pharmaceutical products) we considered in this work. A comparison of the two dryers and an evaluation of energy efficiency were also carried out. It was found that drying should be carried out with relatively low temperatures and high air fluxes for both the large- and small-scale dryers in order to maximize the energy efficiency.