4-(2-吡啶偶氮)-间二苯酚光度法测定奶粉中的锌含量

研究了显色剂4-(2-吡啶偶氮)-间二苯酚与锌的显色反应.在pH=9.0的硼砂-盐酸缓冲溶液中,非离子表面活性剂OP存在下.锌与4-(2-吡啶偶氮)-间二苯酚反应形成红色配合物,其最大吸收波长为500nm,表观摩尔吸光系数为6.24×104L·,moL-1·cm-1.锌含量在0～60μg/50mL范围内符合比尔定律.该方法用于测定奶粉中的锌含量测定,加标回收率为97.8%～103.6%,相对标准偏差小于3.6%.     

火焰原子吸收分光光度法测定环境水样中钾和钠

采用火焰原子吸收分光光度法测定环境水样中钾和钠的含量,通过对不同波长条件下钾钠吸光度的比较,选择出最佳灵敏线应用于本机分析试验,过程简单,效果十分理想。方法灵敏度高、线性关系良好、结果准确稳定,检出限钾为0.005mg/L、钠为0.008mg/L。应用此方法测定2种水样中的钾和钠,相对标准偏差1.2%～1.9%,回收率95.2%～103.2%。     

离子色谱法测定大气中乙酸盐

用碳酸钠-碳酸氢钠混合液吸收大气中的乙酸盐,离子色谱法测定吸收液中的乙酸盐含量,根据采气量算出大气中乙酸盐含量。AC-检出限为0.060mg/L,当采气体积为100L时,最低检出浓度为0.006mg/m3,测定方法的相关系数r=0.9956,相对标准偏差<5%,样品回收率为93.6-95.8%。     

ICP-MS法与石墨炉原子吸收法测定矿山废水中铊含量的比较

通过对比测定矿山废水中铊含量的ICP-MS法与石墨炉原子吸收法,为选矿废水中铊的测定提供可靠的方法,在确定ICP-MS法与石墨炉原子吸收法工作曲线的基础上,对矿山选矿废水中铊进行测定并确定最佳测定方法,检测结果中石墨炉原子吸收法的测定结果 1.57μg/L,加标回收率为94%~108%;ICP-MS法的测定结果为1.92μg/L,加标回收率为86%~98%;结果表明,对于复杂水体中铊的测定,石墨炉原子吸收法具有较高的抗干扰能力、重现性、准确度和精密度,即矿山选矿废水中铊的含量检测石墨炉原子吸收法优于ICP-MS方法。     

用分光光度法测定电镀废水中的微量铅(Ⅱ)

在OP乳化剂存在下,研究了Pb2 和双硫腙的配位显色反应.试验结果表明,在pH=5.0的HAc-NaAc缓冲溶液中,有色溶液的最大吸收波长为500 nm,摩尔吸光系数为4.8×104 L/(mol·cm),Pb2 浓度在0～1.2 mg/L范围内符合比耳定律,加标回收率为98.5%～102.1%之间.本法用于测定处理电镀废水中的微量铅,方法简单易行,结果可靠.     

4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯光度法测定电镀废水中的微量镍(Ⅱ)

4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯(5-Cl-PADAB)可与镍发生灵敏的显色反应,生成稳定的配位化合物。基于此建立了一种测定电镀废水中微量镍的光度法。结果表明:在2.0 mol/L HCl介质中,5-Cl-PADAB与Ni(Ⅱ)反应生成摩尔比2∶1的稳定配位化合物,其最大吸收波长为565 nm,表观摩尔吸光系数为6.42×104 L/(mol.cm),Ni(Ⅱ)含量在0～1.0 mg/L内符合比尔定律;该方法用于测定电镀废水中微量镍,结果与催化-分光光度法相符,相对标准偏差小于4.0%,加标回收率为98.5%～101.8%。     

离子色谱法测定空气中的氮氧化物和氯化氢含量

阐述了离子色谱法测定空气和废气中氮氧化物、氯化氢的含量的方法与步骤。测定结果显示,氮氧化物和氯化氢的检测限分别为0.08mg/L、0.02mg/L,该方法的回收率分别为96.5%～102.1%,98.5%～103.7%,线性范围分别为0.00-l00mg/L,0.00-100mg/L,是一种简单、快速、可靠测定空气和废气中氮氧化物、氯化氢含量的好方法。     

原子吸收火焰法测定复混肥中钾含量

采用原子吸收火焰法在404.4nm条件下测定复混肥中钾含量,其线性较好,精度也较高,最高限可以检测到200mg/L,回收率为97.2%～99.8%.     

改性蛭石吸附电镀废水中铜离子的研究

将天然蛭石进行处理制备出改性蛭石.在静态条件下,对改性蛭石处理含铜废水进行了研究,探讨了改性蛭石用量、废水酸度、接触时间、温度对除铜效果的影响.结果表明,在废水pH值5.0～7.0、Cu2 浓度0～100 mg/L范围内,按Cu2 与改性蛭石质量比为1/30投加改性蛭石进行处理,Cu2 去除率可达98%以上,且处理后废水pH值为7.62,废水近中性.含Cu2 为28.6 mg/L的电镀废水经改性蛭石处理后,废水中Cu2 含量为0.36 mg/L,Cu2 含量显著低于国家排放标准.     

一次性筷子中过氧化氢含量的测定

本文用高锰酸钾法测定一次性筷子中的过氧化氢测定的含量,选择了日常的一次性筷子,浸泡10h后用滤纸过滤,用高锰酸钾溶液滴定,并扣除其他还原性组分的干扰。结果发现含量在158 mg/L～184mg/L,RSD在0.2%～0.5%之间。过氧化氢较高含量时,回收率能达到90%以上。本法快速、简单、适用于一次性筷子中过氧化氢的测定。     

Penicillium digitatum immobilized on pumice stone as a new solid phase extractor for preconcentration and/or separation of trace metals in environmental samples

This study presents a column solid phase extraction procedure based on column biosorption of Cu(II), Zn(II) and Pb(II) ions on Penicillium digitatum immobilized on pumice stone. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions such as: pH values, amount of solid phase, elution solution and flow rate of sample solution were evaluated for the quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes has also been investigated. The recoveries of copper, zinc and lead under the optimum conditions were found to be 97+/-2, 98+/-2 and 98+/-2%, respectively, at 95% confidence level. For the analytes, 50-fold preconcentration was obtained. The analytical detection limits for Cu(II), Zn(II) and Pb(II) were 1.8, 1.3 and 5.8 ng mL(-1), respectively. The proposed procedure was applied for the determination of copper, zinc and lead in dam water, waste water, spring water, parsley and carrot. The accuracy of the procedure was checked by determining copper, zinc and lead in standard reference tea samples (GBW-07605).     

油内比和表面活性剂浓度对（稀型）乳状液膜工业过程的影响

在当前破乳技术的基础上,用稀型乳状液膜法治理粘胶纤维工业酸性含锌废水、选择稀型乳状液的油内比Ｒｏｉ大于３,表面活性剂Ｔ１５４的体积分数降至０．６％的条件,在工业上实现了含锌废水的处理,这过程既无二次污染,又 收锌资源,具有一定的经济效益。     

Electroleaching and electrodeposition of zinc in a single-cell process for the treatment of solid waste

This work deals with zinc beneficiation of industrial solid waste by an electrochemical technique combining electroleaching and electrodeposition in a single-cell process. This technique is based on leaching of the solid waste by the protons generated at the anode and migration of the resulting ions toward the cathode where deposition takes place. A laboratory cell was built for testing the method. It consisted of three compartments, two electrode compartments and a solid waste chamber placed between these. Catholyte and anolyte were sulphuric/sulphate solutions at optimised concentrations. Experiments were first carried out using a zinc solution and an inert matrix in the central compartment, then using a synthetic waste prepared by dispersing zinc oxide in silicon dioxide. Best performance was obtained with treatment duration of 6h, at 4.5Adm(-2) and with catholyte circulation. In this case, a 97% of zinc oxide lixiviation and 75% of zinc-plated were achieved.     

A study on the dewatering of industrial waste sludge by fry-drying technology

In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying is very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m² °C was used to dry industrial wastewater sludge. Also waste oil was used in the fry-drying process, and because the oil's boiling point is between 240 and 340 °C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 120 and 170 °C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 5300 kcal/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The wastewater sludge used in this study was the designated waste discharged from chemical, leather and plating plants. These samples varied in characteristics, especially with regard to heavy metal concentration. After drying the three kinds of wastewater sludge at oil temperatures 160 °C for 10 min, it was found that the water content in the sludge from the chemical, leather, and plating plants reduced from 80.0 to 5.5%, 81.6 to 1.0%, and 65.4 to 0.8%, respectively. Furthermore, the heat values of the sludge from the chemical, leather, and plating plants prior to fry-drying were 217, 264, and 428 kcal/kg, respectively. After drying, these values of sludge increased to 5317, 5983 and 6031 kcal/kg, respectively. The heavy metals detected in the sludge after drying were aluminum, lead, zinc, mercury, and cadmium. Most importantly, if the dried sludge is used as a solid fuel, these heavy metals can be collected from the dust collector after combustion.     

Integrated treatment scheme for rubber thread wastewater: sulfide precipitation and biological processes

In this study, acidic latex wastewater containing high average zinc and acetic contents of 816mgL(-1) and 20,862mgCODL(-1), respectively, was treated successfully by a series of chemical and biological processes without any addition of acid or base for pH adjustment. Total dissolved solids of the treated effluent increased by only 1.1-fold on average for sulfide precipitation as compared to 2.8-fold for the hydroxide strategy. The oxidation-reduction potential (ORP) value of 0mV was used successfully as an indicator for optimum sulfide addition which consistently provided an appreciable reduction in effluent concentrations to less than 1 and 2mgL(-1) for zinc and residual sulfide, respectively. The anaerobic filter was very stable in handling the chemically treated wastewater up to the organic loading rate of 11.8gCODL(-1)day(-1) with an average efficiency of 92%. Methane production and biomass yield were 0.32L(gCOD(removed))(-1) and 0.014gVSS (gCOD(removed))(-1), respectively. For the activated sludge process, the optimum sludge age and hydraulic retention time were 30 and 0.8 days, respectively, which are equivalent to the organic loading rates of 2.50gCODL(-1)day(-1) or 2.13gBODL(-1)day(-1). Under these optimum conditions, average removal efficiencies for COD and BOD were 96.6 and 99.4%. Average soluble COD, BOD and suspended solids in the effluent were 71, 11 and 38mgL(-1), respectively. This integrated treatment scheme was proven to be an effective approach for highly polluted and toxic rubber thread wastewater.     

Use of fly ash,phosphogypsum and red mud as a liner material for the disposal of hazardous zinc leach residue waste

Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The release of large quantities of heavy metals into the environment has resulted in a number of environmental problems. The present study investigated the safe disposal of the zinc leach residue waste using industrial residues such as fly ash, phosphogypsum and red mud. In the study, leachability of heavy metals from the zinc leach residue has been evaluated by mine water leaching procedure (MWLP) and toxicity characteristic leaching procedure (TCLP). Zinc removal from leachate was studied using fly ash, phosphogypsum and red mud. The adsorption capacities and adsorption efficiencies were determined. The adsorption rate data was analyzed according to the pseudo-second-order kinetic, Elovich kinetic and intra-particle diffusion kinetic models. The pseudo-second-order kinetic was the best fit kinetic model for the experimental data. The results show that addition of fly ash, phosphogypsum and red mud to the zinc leach residue drastically reduces the heavy metal content in the leachate and could be used as liner materials.     

Manganese recovery from secondary resources: a green process for carbothermal reduction and leaching of manganese bearing hazardous waste

During the hydrometallurgical extraction of zinc by electrowinning process, a hazardous solid waste called anode mud is generated. It contains large quantity of manganese oxides (55-80%) and lead dioxide (6-16%). Due to the presence of a large quantity of lead, the anode mud waste is considered hazardous and has to be disposed of in secure landfills, which is costly, wastes available manganese and valuable land resources. For recovery of manganese content of anode mud, a process comprising of carbothermal treatment using low density oil (LDO) followed by sulphuric acid leaching is developed.     

Equilibrium studies for the sorption of zinc and copper from aqueous solutions using sugar beet pulp and fly ash

In the present work, the abilities of native sugar beet pulp (SBP) and fly ash (FA) to remove copper (Cu(2+)) and zinc (Zn(2+)) ions from aqueous solutions were compared. The SBP and FA, an industrial by-product and solid waste of sugar industry, were used for the removal of copper and zinc from aqueous water. Batch adsorption experiments were performed in order to evaluate the removal efficiency of SBP and lignite-based FA. The effect of various operating variables, i.e. initial pH, adsorbent dose, initial metal ion concentration, and time on adsorption of copper and zinc onto the SBP and FA, has been studied. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact. As much as 60-97% removal of copper and zinc for SBP and FA are possible in about 60 min, respectively, under the batch test conditions. Uptake showed a pH-dependent profile. The overall uptake for the SBP is at a maximum at pH 5.5 and gives up to 30.9 mg g(-1) for copper and at pH 6.0 and gives 35.6 mg g(-1) for zinc for SBP, which seems to be removed exclusively by ion exchange and physical sorption. Maximum adsorption of copper and zinc occurred 7.0 and 7.84 mg g(-1) at a pH value of 5.0 and 4.0 for FA, respectively. A dose of 8 g l(-1) of SBP and 8 g l(-1) FA were sufficient for the optimum removal of both the metal ions. The sorption data were represented by the Freundlich for SBP and the Langmuir and Freundlich for FA. The sorption data were better represented by the Langmuir isotherm than by the Freundlich one for FA in the adsorption of zinc ion, suggesting that the monolayer sorption, mainly due to ion exchange. The presence of low ionic strength or low concentration of Na and Cl ions does not have a significant effect on the adsorption of these metals by SBP and FA. The SBP and FA are shown to be effective metal adsorbents for these two metals.     

生活废热水余热利用的实验研究

理论研究显示,以生活废热水为热源的热泵热水器比空气源热泵热水器有更好的节能效果和更广的应用区域,但对非公共浴室的生活废热水源热泵热水器的实践研究和应用仍较少。以仲恺农业工程学院学生生活废水的使用和排放情况为基础,设计了可用于家庭、集体宿舍和宾馆房间的户式生活废热水源热泵热水系统,并模拟多种运行工况进行了实验研究,为生活废热水源热泵热水器的工程设计提供依据。研究表明,该系统能效比高,节能效果优于其他热水加热方式。     

Recovery of metals from waste printed circuit boards by a mechanical method using a water medium

Research on the recycling of waste printed circuit boards (PCB) is at the forefront of environmental pollution prevention and resource recycling. To effectively crush waste PCB and to solve the problem of secondary pollution from fugitive odors and dust created during the crushing process, a wet impacting crusher was employed to achieve comminution liberation of the PCB in a water medium. The function of water in the crushing process was analyzed. When using slippery hammerheads, a rotation speed of 1470 rpm, a water flow of 6 m³/h and a sieve plate aperture of 2.2 mm, 95.87% of the crushed product was sized less than 1 mm. 94.30% of the metal was in this grade of product. Using smashed material graded −1 mm for further research, a Falcon concentrator was used to recover the metal from the waste PCB. Engineering considerations were the liberation degree, the distribution ratio of the metal and a way to simplify the technology. The separation mechanism for fine particles of different densities in a Falcon concentrator was analyzed in detail and the separation process in the segregation and separation zones was deduced. Also, the magnitude of centrifugal acceleration, the back flow water pressure and the feed slurry concentration, any of which might affect separation results, were studied. A recovery model was established using Design-Expert software. Separating waste PCB, crushed to −1 mm, with the Falcon separator gave a concentrated product graded 92.36% metal with a recovery of 97.05%. To do this the reverse water pressure was 0.05 MPa, the speed transducer frequency was set at 30 Hz and the feed density was 20 g/l. A flow diagram illustrating the new technique of wet impact crushing followed by separation with a Falcon concentrator is provided. The technique will prevent environmental pollution from waste PCB and allow the effective recovery of resources. Water was used as the medium throughout the whole process.