散射光下铁(Ⅲ)-丙酮酸盐配合物还原铬(Ⅵ)的研究

研究了在散射光下铁（Ⅲ）-丙酮酸盐配合物对铬（Ⅵ）的光还原反应;考察了溶液pH、铁（Ⅲ）、丙酮酸钠、铬（Ⅵ）浓度对反应的影响;分析了铬（Ⅵ）光还原反应的动力学。实验结果表明：铁（Ⅲ）-丙酮酸盐配合物体系能在较弱的散射光下还原铬（Ⅵ）。在铬（Ⅵ）浓度为19．2μmol／L、铁（Ⅲ）浓度为10．0μmol／L、丙酮酸钠浓度为240μmol／L、pH为3．0、光照240min的条件下,铬（Ⅵ）的还原率达到99．7％。从表观动力学方程的反应级数看,铁（Ⅲ）的级数（0．83）最高,铁（Ⅲ）浓度是影响铬（Ⅵ）光还原反廊速率的主要因素．铁（Ⅱ）是铬（Ⅵ）光还原的主要还原剂。     

复方头孢氨苄胶囊荧光熄灭法测定水中的铬(Ⅵ)

基于铬(Ⅵ)对复方头孢氨苄胶囊(CCC)的荧光熄灭,建立了测定水中铬(Ⅵ)的方法。在pH为4.2的HCl-NaAc缓冲溶液中,最大激发波长和发射波长分别为351nm和433nm、CCC加入量为100mg/L时,铬(Ⅵ)浓度的测定范围为2.00×10-6~5.00×10-3mol/L,检出限为6.25×10-7mol/L。该法受共存物的干扰相对较小,可用于测定环境水样中的铬(Ⅵ)浓度。     

Na_5[Ce(ZrMo_(11)O_(39))]·xH_2O杂多酸盐的光催化降解性能

采用傅立叶变换红外光谱仪和X射线衍射仪对自制的Keggin型结构的Na5[Ce(ZrMo11O39)]·xH2O杂多酸盐进行了表征,并研究了Na5[Ce(ZrMo11O39)]·xH2O杂多酸盐对模拟酸性绿B印染废水的光催化降解效果。实验结果表明:合成的杂多酸盐具有Keggin型结构;在模拟酸性绿B印染废水初始质量浓度为10mg/L、初始pH为6、杂多酸盐加入量为0.8g/L的条件下,光照160min后模拟印染废水中酸性绿B的降解率达79.49%。动力学分析结果表明,降解反应符合一级反应动力学模型。     

微生物法处理含铬(Ⅵ)废水的研究

采用硫酸盐还原菌处理含铬(Ⅵ)废水，研究了其去除铬(Ⅵ)的最适宜工艺条件。实验表明，该菌的适用范围广，处理含铬废水的能力强。在菌液与废液体积比为1．0：1、铬(Ⅵ)质量浓度为150mg／L条件下处理36h，铬(Ⅵ)去除率达99．9％。     

以硫铁矿烧渣为原料制备铁黄

用硫铁矿烧渣精制的FeSO4和N aOH为原料制备铁黄晶种,在二次氧化过程中用滴加氨水的方法制备铁黄颜料,考察了影响晶种质量及铁黄质量的诸多因素。实验得出的铁黄晶种制备的工艺条件为:温度25℃,碱比0.3,Fe2 初始浓度1m o l/L,通氧速率3.0L/(L.m in);二次氧化的工艺条件为:溶液pH3~4,晶种比25%,通氧速率4.0L/(L.m in)。经检测,用该法制备得到的铁黄产品质量达到中华人民共和国化工行业标准HG/T2249—91《氧化铁黄颜料》一级品标准。     

铬(Ⅵ)-溴酸钾-乙基紫催化光度法测定水中痕量铬(Ⅵ)

在磷酸介质中,利用铬(Ⅵ)对溴酸钾氧化乙基紫褪色反应有灵敏的催化作用,建立了测定痕量铬(Ⅵ)的新型催化光度法,考察了该褪色反应的最佳条件。在反应温度85℃、反应时间5m in、以醋酸钠作抑制剂的条件下,体系可稳定60m in以上,测定波长为600nm,方法的检出限为1×10-9g/mL,线性范围为0.004~0.094μg/mL,相对标准偏差小于2.5%,加标回收率为97.0%~101.5%。该法简便、灵敏、选择性好,用于水样中痕量铬(Ⅵ)的测定,结果令人满意。     

化学沉淀法预处理稀土精矿分解废水

采用化学沉淀法对稀土精矿分解废水进行预处理,实验结果表明,当pH9.0、n(M g2 )∶n(NH 4)∶n(PO34-)=3.5∶1∶1.5时,废水中NH3-N的质量浓度由8 370m g/L降为1 420m g/L,去除率为83%。为了不增加出水中PO34-污染物的浓度,向上层清液中加入相应量的CaC l2.2H2O。当n(Ca2 )∶n(PO34-)=9∶1时,完成沉淀反应,再调整上层清液的pH为10,搅拌后,上层清液中PO34-的质量浓度降为0.18m g/L。     

铁矿石烧结烟气脱硫灰处理含铬废水

在分析铁矿石烧结烟气脱硫灰成分的基础上,利用脱硫灰中的亚硫酸盐还原废水中的Cr(Ⅵ),再加碱中和,通过沉淀去除铬。在初始废水pH 1.0、脱硫灰加入量0.06 g/mg(以Cr(Ⅵ)计)、振荡转速160 r/min、振荡时间25 min、中和pH 7.5的最佳工艺条件下处理模拟含铬废水,Cr(Ⅵ)质量浓度由10.00 mg/L降至0.18 mg/L,去除率达98.2%。最佳工艺条件下处理3种实际含铬废水,处理后出水的Cr(Ⅵ)和总铬的质量浓度及pH均满足GB 8978—1996《污水综合排放标准》。实现了对脱硫灰的综合利用、化害为利和以废治废的目标。     

D401与N-117负载Fe(Ⅱ)非均相Fenton法催化降解苯酚

分别采用D401和N-117负载Fe(Ⅱ)制备非均相Fenton催化剂,探讨两种催化剂在不同初始溶液pH、初始H_2O_2质量浓度和保存条件下,催化降解苯酚的效果和铁溶出情况。结果表明:两种催化剂均能拓展Fenton反应pH范围;D401负载Fe(Ⅱ)催化苯酚降解速率较快,苯酚降解率随初始溶液pH升高而下降,溶出铁催化的均相Fenton反应是苯酚降解的主要原因;N-117负载Fe(Ⅱ)催化剂苯酚降解速率随初始溶液pH升高而下降,非均相Fenton反应是主要反应过程;初始H_2O_2质量浓度升高能使D401负载Fe(Ⅱ)的溶出总铁质量浓度显著升高,但对N-117负载Fe(Ⅱ)影响很小;水中较高的DO能显著降低两种催化剂的苯酚降解效果。     

生物还原-化学沉淀法自烟气中的SO2制备ZnS

采用生物还原—化学沉淀法自烟气中的SO2制备ZnS,将含有Zn(OH)2杂质的粗品ZnS通过化学提纯制得高纯度ZnS。实验结果表明,采用NH4C l-NH3.H2O混合液对含有Zn(OH)2杂质的粗品ZnS进行提纯的优化条件为:每500m g粗品ZnS加入NH4C l与NH3.H2O摩尔比为1∶1、两组分浓度均为3.0m o l/L的10mLNH4C l-NH3.H2O混合液。X射线衍射分析表明,提纯后的产物粉末全部为ZnS,其纯度与ZnS标准试样相当。     

Connectivity of Hybrid Polymer by Tight Binding Approximation: Example of (Si(CH3)2) n (OSiO) p (OH) q

We computed by a tight binding calculation taking into account hybridization, the total electronic energy of different connectivities (amorphous, fractal and linear) of (Si−(CH₃)₂) _n −(OSiO) _p (OH) _q . We found that the total electronic energy of the amorphous connectivity was the smallest as a function of the number of atoms contained by the hybrid polymer. As the total electronic energy is linked to the stability, we may say that the connectivity of such hybrid polymer has the highest stability for the amorphous connectivity.     

Influence of poly(bisphenol A carbonate) and poly(ethylene terephthalate) on poly(vinyl chloride) dehydrochlorination

Recycling of poly(vinyl chloride) (PVC) waste is a serious problem because of its high chlorine content. Dehydrochlorination of PVC-containing polymer waste produces solid residue char, for which conversion to pyrolysis oil in a petrochemical plant seems to be an attractive way of recycling PVC waste. Unfortunately, some polymer admixtures react with HCl and cause formation of chloroorganic compounds in a char. This article describes the influence of polycarbonates and poly(ethylene terephthalate) on thermal feedstock recycling of PVC wastes using a two-stage method. It was found that the presence of polycarbonate causes the formation of small amounts of benzyl chloride and other chloroaryl or chloroalkylaryl compounds. Poly(ethylene terephthalate) interacts with HCl forming significant amounts of various chlorocompounds – mainly chloroethyl esters of terephthalic and benzoic acids, but derivatives possessing chlorine directly connected to the aromatic ring are also formed.     

Poly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materials

Granular cornstarch was coated with several biodegradable polymers in an effort to improve the mechanical properties of starch-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composites. Only samples containing poly(ethylene oxide) (PEO)-coated granular starch showed a large improvement in tensile properties over uncoated starch. For example, a 50/50 blend of PEO-coated starch and PHBV had a tensile strength of 19 MPa and an ultimate elongation of 23%, compared to 10 MPa and 11% for a similar blend containing uncoated starch. PEO may act as an adhesive between the starch and the PHBV and/or increase the toughness and resistance to crack growth of PHBV around the starch granules.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.     

用喷射鼓泡反应器进行烟气脱硫

介绍了采用喷射鼓泡反应器处理烟气量为7 000~10 000 m3/h的软锰矿浆烟气脱硫中试试验。试验中,对喷射鼓泡反应器及系统的阻力进行了测定,考察了不同品位、不同液固比的软锰矿条件及系统连续运行时的脱硫率和锰浸出率。中试表明,在液固比为(2~3)∶1、矿粉粒度约为100目的连续运行条件下,无论是选用品位高的钦锰矿还是品位低的软锰矿,系统运行稳定,且脱硫率保持在90%以上,锰浸出率在70%以上。吸收液经净化处理后得到的MnSO4.H2O产品可达到国家GB1622—86标准。     

Chemical looping combustion (CLC) of municipal solid waste (MSW)

Chemical Looping Combustion (CLC) has been found to be a better alternative in converting Municipal Solid Waste (MSW) to energy and has the potential to reduce the generation of dioxins due to the inhibition of the de-novo synthesis of dioxins. This study comprehensively reviews the experimental studies of CLC of MSW, the oxygen carriers, reactor types, performance evaluation, and ash interaction studies. Modeling and simulation studies of CLC of MSW were also critically presented. Plastic waste is MSW’s most studied non-biomass component in MSW under CLC conditions. This is because CLC has been shown to reduce the emission of dioxins and furans, which are normally emitted during the conventional combustion of plastics. From the several oxygen carriers tested with MSW’s CLC, alkaline earth metals (AEM) modified iron ore was the most effective for reducing dioxin emissions, improving combustion efficiency and carbon conversion. Also, oxygen carriers with supports were more reactive than single carriers and CaSO₄/Fe₂O₃ and CaSO₄ in silica sol had the highest oxygen transport ability. Though XRD analysis and thermodynamic calculations of the reacted oxygen carriers yielded diverse results due to software computation constraints, modified iron ore produced less HCl and heavy metal chlorides compared to iron ore and ilmenite. However, alkali silicates, a significant cause of fouling, were observed instead. The best reactor configuration for the CLC of MSW is the fluidized bed reactor, because it is easy to obtain high and homogeneous solid–gas mass transfer. Future research should focus on the development of improved oxygen carriers that can sustain reactivity after several cycles, as well as the system’s techno-economic feasibility.

     

A grey-relation-based method (GRM) for thermogravimetric (TG) data analysis

Journal of Material Cycles and Waste Management - Thermogravimetric analyzer was applied to analyze 22 solid materials and their mixtures at a heating rate of 10 K min−1...     

Poly(hydroxyalkanoate) Biosynthesis from Crude Alaskan Pollock (Theragra chalcogramma) Oil

Six strains of Pseudomonas were tested for their abilities to synthesize poly(hydroxyalkanoate) (PHA) polymers from crude Pollock oil, a large volume byproduct of the Alaskan fishing industry. All six strains were found to produce PHA polymers from hydrolyzed Pollock oil with productivities (P; the percent of the cell mass that is polymer) ranging from 6 to 53% of the cell dry weight (CDW). Two strains, P. oleovorans NRRL B-778 (P = 27%) and P. oleovorans NRRL B-14682 (P = 6%), synthesized poly(3-hydroxybutyrate) (PHB) with number average molecular weights (M_n) of 206,000 g/mol and 195,000 g/mol, respectively. Four strains, P. oleovorans NRRL B-14683 (P = 52%), P. resinovorans NRRL B-2649 (P = 53%), P. corrugata 388 (P = 43%), and P. putida KT2442 (P = 39%), synthesized medium-chain-length PHA (mcl-PHA) polymers with M_n values ranging from 84,000 g/mol to 153,000 g/mol. All mcl-PHA polymers were primarily composed of 3-hydroxyoctanoic acid (C_8:0) and 3-hydroxydecanoic acid (C_10:0) amounting to at least 75% of the total monomers present. Unsaturated monomers were also present in the mcl-PHA polymers at concentrations between 13% and 16%, providing loci for polymer derivatization and/or crosslinking. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Polylactic Acid (PLA) Biocomposites Filled with Waste Leather Buff (WLB)

A large amount of leather waste is generated from tanning industries and most of which are disposed of landfill or discharged into the natural water bodies without any treatment, causing environmental problems. The aim of this study is to develop eco-biocomposites using waste leather buff (WLB) as filler in Polylactic acid (PLA) matrix to reduce the environmental issues and provide sustainable solution. WLB/PLA composites were prepared by twins-screw micro extruder varying the WLB content from 2% to 30 wt%. These composite were extensively characterise by several techniques. Tensile properties of the composites showed addition of WLB resulted in improvement of tensile property of composite and reduction in percentage crystallinity of PLA matrix observed with increase in WLB content. The effect of WLB on properties of interfacial adhesion and dispersion in WLB/PLA composites were studied by SEM. Wettability of composites was tested by contact angle and water absorption studies. WLB/PLA composite showed increase in water absorption with WLB loading. These WLB/PLA composite could be used to develop low cost eco-friendly product material.     

Engineering and Processing of Poly(HydroxyButyrate) (PHB) Modified by Nano-sized Graphene Nanoplatelets (GNP) and Amino-Functionalized Silica (A-fnSiO<Subscript>2</Subscript>)

Manufacturing of plastics by biodegradable polymers can reduce the environmental impact and limit the recourse to non-renewable resources. Physical, chemical and mechanical properties of biodegradable polymers cannot often be comparable with petroleum-based plastics. However, the modification of bioplastics by physical and chemical routes can improve their performance. In this work, Poly(HydroxyButyrate) PHB is reprocessed by the dispersion of graphene nano-platelets as well as by the dispersion of Amino-Functionalized Nano-Silica (A-fnSiO₂). Modification of the PHBs after compounding and pelletizing was evaluated by Fourier Transform Infrared. Thermal analysis was performed by Differential Scanning Calorimetry after extrusion and compression moulding. Hardness and scratch performance of the polymers were measured on compression molded substrates by pencil and progressive and constant load scratch tests. Chemical resistance was evaluated on compression molded substrates by dipping in aggressive acidic, basic and saline aqueous solutions. In conclusion, the PHBs modified by the graphene nanoplatelets were found to be very promising, featuring good chemical inertness, hardness and mechanical strength.