KMnO4/H2SO4引发制备淀粉改性絮凝剂的研究

以高锰酸钾为引发剂,制备淀粉-丙烯酰胺接枝共聚物.研究酸浓度、引发剂浓度、单体浓度、温度和加料方式对接枝反应的影响.结果表明,少量KMnO4(0.45mmol·l-1)和H2SO4(0.8mmol·l-1)可有效引发淀粉-丙烯酰胺接枝共聚反应,接枝效率达到90%以上,分子量大大提高,对高岭土的絮凝效果较好.     

KMnO4/H2SO4引发制备淀粉改性絮凝剂的研究

以高锰酸钾为引发剂,制备淀粉-丙烯酰胺接枝共聚物.研究酸浓度、引发剂浓度、单体浓度、温度和加料方式对接枝反应的影响.结果表明,少量KMnO4(0·45mmol·l-1)和H2SO4(0·8mmol·l-1)可有效引发淀粉-丙烯酰胺接枝共聚反应,接枝效率达到90%以上,分子量大大提高,对高岭土的絮凝效果较好.     

SAS/IPPA/AA三元共聚物对碳酸钙阻垢性能的研究

以水为溶剂,过硫酸铵为引发剂,丙烯磺酸钠、异丙烯膦酸和丙烯酸为单体,合成了三元共聚物丙烯磺酸钠/异丙烯膦酸/丙烯酸(SAS/ IPPA/AA),研究了共聚物在不同水质条件下对CaCO3的阻垢性能,探讨了共聚物浓度、pH值、钙离子浓度、碳酸根离子浓度和温度等条件对CaCO3的阻垢性能的影响,结果显示,在共聚物用量为18mg·l-1时,可使阻垢率达到100%.     

两性木质素接枝共聚物的聚合反应与离子化改性

研究碱木质素与复合单体在水相中接枝共聚,以Mannich反应进一步对接枝产物进行阳离子化改性.结果表明:在70℃±5℃下进行木质素与复合单体接枝共聚反应,当pH值为7.0-8.0、反应时间为2h-2.5h,获得较理想的接枝效果,过硫酸盐引发效果优于过氧化氢,引发剂适宜的反应浓度约为10mmol·l-1.共聚物阳离子化改性的适宜条件为:醛、胺与木质素的质量比为0.5∶1.2∶1,反应温度60℃-70℃,反应时间2h,反应产物为一种具有阴、阳离子两性基团的木质素聚合物. 以丙酮分离产物,当体积比为0.75时,获得产物与水较好的分离效果. 红外光谱分析表明,木质素与复合单体实现了有效的接枝共聚和离子化改性.     

天然改性淀粉絮凝剂的合成与应用

以硝酸铈铵为引发剂,通过接枝共聚反应,在淀粉(Starch)骨架上引入丙烯酰胺(AM),制得St-AM接枝物.在引发剂用量为1.1 mmol·l-1,淀粉与单体质量配比为1∶ 3,25℃下反应3h,接枝物黏度可达587.83 ml·g-1,能使煤泥水中的细泥颗粒形成较大的絮团而快速沉降,固液分离效果好.用合成的絮凝剂进行了水处理试验,结果表明,当接枝物用量为50g·t-1干煤泥,辅以凝聚剂用量1.5kg·t-1干煤泥能有效解决选煤厂煤泥水中细粒含量多、压滤处理困难的问题,滤饼水分可控制在25%,滤液浓度在60g·l-1左右,与聚丙烯酰胺(PAM)对煤泥水和高岭土悬浮体絮凝作用相比,该接枝共聚物具有价廉、无毒、絮凝效果好等特点.     

木质素接枝改性影响因素的研究

对碱法麦草制浆黑液酸法回收的木质素与丙烯酰胺接枝共聚反应进行了试验研究.结果表明,接枝共聚反应的适宜条件为:丙烯酰胺单体用量1.0mol·1-1,过硫酸钾引发剂浓度1.0×10-2mol·1-1,反应温度70℃,固液比1:50(W/W),反应时间4h.木质素与木质素接枝聚合物以及聚丙烯酰胺的红外光谱表明,木质素与丙烯酰胺之间发生了接枝共聚反应.     

羧甲基纤维素钠基复合调湿材料的制备与性能

调湿剂能依靠自身的吸放湿性能改变空气里的湿度.采用羧甲基纤维素钠(CMC)为基质,从调湿性能筛选出氯化镁和氯化钙两种中性无机盐,采用单因素法确定基质和无机盐的最佳配比为m(基质):m(无机盐)=1:1,挤条烘干得调湿剂A和B.调湿剂A和B在高湿度(70%RH)下有良好的吸湿性能.吸湿量分别达到33%和67%,高于普遍采用的干燥剂硅胶,5 h基本达到放湿平衡.在调湿剂的外面包裹金属氧化物二氧化锰得复合剂,实验结果表明对于微最的甲醛具有一定的吸附效果,在72 h内将初始质量浓度为1 000 μg·m-3的甲醛降到216μg·m-3.且实验表明复合剂仍有较高的吸湿量.     

利用新复合引发体系合成P(DMDAAC-AM)共聚物

采用新的复合引发体系及助剂,在水溶液中合成了分子量较高而且速溶的P(DMDAAC-AM)共聚物．着重研究各种引发剂和助剂的浓度、引发及烘干温度、反应时间等因素对聚合反应的影响,得出最佳合成工艺及配方．利用IR、透射电镜和扫描电镜对产品进行分析．     

响应面法优化制备螯合絮凝剂巯基乙酰化聚丙烯酰胺

以聚丙烯酰胺(PAM)和巯基乙酸(TGA)为原料,通过化学反应制备出对Cu(Ⅱ)具有螯合絮凝作用的新型絮凝剂巯基乙酰化聚丙烯酰胺(MAPAM).以水样中Cu(Ⅱ)的去除率为考察对象,在单因素实验的基础上,选取MAPAM制备的影响因素,采用正交试验法和响应曲面法中常用的中心复合设计模型对MAPAM的制备条件进行了优化.结果表明,响应曲面法确定的MAPAM制备条件最优;该法建立的二次多项式模型的回归项极显著(P0.0001),失拟项不显著(P0.05),复相关系数R2为0.9412,模型选择合理.MAPAM最佳制备条件为:PAM相对分子质量为25万,PAM浓度为1.0%,反应物TGA和PAM(结构单元)物质的量比为3.2∶1,反应介质pH值为3.6,反应温度为25℃,反应时间为2.1 h.该优化条件下制备的MAPAM对Cu(Ⅱ)最高去除率可达95.62%,与模型预测值(96.78%)接近,相对偏差仅为-1.20%,模型与实际拟合良好.     

响应面法优化固定粘红酵母细胞条件及生物转化制L-苯丙氨酸

采用响应面分析法对影响粘红酵母细胞固定化的4个主要因素——单体浓度、交联剂浓度、包埋量、包埋时间进行了优化.首先用Plackett-Burman法设计实验对以上4个影响因素进行了评价,并筛选出显著影响因素——单体浓度和包埋量;第2步用最陡爬坡实验逼近以上两因素最优水平;最后由中心复合实验及响应面分析确定主要影响因素的最佳条件.固定化粘红酵母细胞的最优包埋条件为:单体浓度16.7%,包埋量43%,交联剂浓度2.0%,包埋时间45min.在此条件下得到的固定化细胞与游离细胞相比,酶活保留率可达63%,较优化前提高了31%.实验室制备试验中L-苯丙氨酸(L-Phe)积累浓度可达53.3g/L,与该菌株的中试游离整细胞一次批式转化产L-Phe浓度30g/L比较,产率提高了1.8倍.图3表9参15     

Effect of biocides on the precipitation of calcium fluoride in the presence of anionic copolymeric inhibitors

The inhibitory efficiency of anionic copolymers and the effect of the biocides sodium hypochlorite, glutaraldehyde, and tris(hydroxymethyl)nitromethane on the precipitation behavior of calcium fluoride (CaF₂) were studied. The efficiency of polymeric inhibitors was traced from conductivity measurements by using half-life (t_1/2) method. X-ray diffraction parameters have been measured for calcium fluoride scale minerals. An anionic copolymer (K-798) acts as one of the best inhibitors for the precipitation process of the calcium fluoride in water as compared to K-775. It is assigned to the fact that the copolymer (K-798) contains both sulfonic acid and sulfonated styrene groups while the polymer (K-775) having only the sulfonic acid group. It was further observed that the biocides have no appreciable effect on the performance of the anionic polymeric inhibitors.     

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

PVDF blended different graft ratio of PVDF-g-PEGMA were systematically studied. Tuning the amphiphilic copolymer synthesis time to control membrane performance. The PVDF membrane with PVDF-g-PEGMA at 19 h possesses most surface oxygen content. The synthesis time of PVDF-g-PEGMA at 9 h is good for high flux UF membrane. Polyvinylidene fluoride grafted with poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) was synthesized using atomic transfer radical polymerization (ATRP) at different reaction times (9 h, 19 h, and 29 h). The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixture containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF-g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping more PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L·m⁻²·h⁻¹, 1068 L·m⁻²·h⁻¹and 1179 L·m⁻²·h⁻¹, respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.     

有机污染物对发光菌和鱼的毒性相关性研究

研究有机污染物对不同水生生物毒性的种间关系有助于探讨有机污染物对水生生物的毒性作用模式。本文应用1 470种有机化合物对发光菌的毒性数据和949种有机化合物对鱼的毒性数据,研究有机化合物对发光菌和鱼的种间毒性作用模式。结果表明,有机化合物对发光菌和鱼的毒性呈正相关,但种间相关性较差。通过计算毒性比率TR值表明多数类别有机化合物具有相似的种间毒性作用模式。基线和弱惰性化合物对发光菌和鱼的毒性均与辛醇水分配系数log Kow具有良好的线性关系,这说明基线和弱惰性化合物在发光菌和鱼体内的残余量CBR值均为一个常数。这些化合物对发光菌和鱼具有相似的毒性作用模式和生物吸收过程。另外,一些亲水性化合物的log TR值具有较大的种间差异,即对发光菌和鱼的毒性效应具有较大的种间差异,表明亲水性化合物对发光菌为反应型化合物,而对鱼为麻醉型化合物。有机化合物对发光菌和鱼的毒性种间相关性通过引入疏水性参数得到了一定的改善,这表明这些亲水性化合物毒性效应的种间差异有一部分归因于有机化合物在发光菌和鱼体内的生物富集不同,而不是由于与生物分子的反应性不同。这些亲水性化合物相对于鱼的腮和皮肤更容易通过发光菌的细胞膜,与生物分子发生化学反应,从而具有较高的毒性效应。Log Kow大于7的化合物对发光菌和鱼均具有较低的毒性,说明有机化合物在生物体内的富集能力对有机化合物剩余毒性的判别起着重要作用。     

Adsorption of arsenic using high surface area magnetites

Magnetites (MEBWx) were prepared by precipitation in 1-butanol/water mixtures of various mole ratios of 1-butanol to water. It was found that the magnetites prepared in the mixture with high mole ratio of 1-butanol to water have high specific surface area. The adsorption isotherms of As(III) and As(V) with the magnetites at 303 K fitted the Langmuir model well. The adsorption capacities of the magnetite prepared in the mixtures were higher than those of the magnetite prepared without 1-butanol. Their adsorption capacities increased with increasing specific surface area.     

聚丙烯酰胺生物降解研究进展

聚丙烯酰胺（PAM）是丙烯酰胺均聚物和各种共聚物的统称，作为一种高技术含量、高附加值的重要化工产品，已广泛应用到工农业生产的各个领域并渗透到人们的日常生活中．过去通常认为聚丙烯酰胺是非常稳定的高分子聚合物，事实上，在自然条件下，聚丙烯酰胺会发生缓慢的物理降解（热、剪切）、化学降解（水解、氧化以及催化氧化）和生物降解，最终生成各种低聚物以及具有神经毒性的剧毒丙烯酰胺单体，对人体造成了极大的间接或直接危害．因此，进行聚丙烯酰胺的降解研究很有意义，而聚丙烯酰胺的生物降解研究领域几乎为空白．参33     

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Adsorption is the most widely used technology for the removal of indoor volatile organic compounds (VOCs). However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity (RH) conditions. In this study, a series of new porous clay heterostructure (PCH) adsorbents with various ratios of micropores to mesopores were synthesized, characterized and tested for the adsorption of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capability, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg·g⁻¹, eight times as much as the amount adsorbed onto conventional activated carbon (AC). Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.     

PBS基共聚物及其模拟降解产物对赤子爱胜蚓急性生态毒性的研究

采用滤纸接触法和自然土壤法,通过急性毒性实验分别研究了20℃时不同分子量PBS（聚丁二酸丁二醇酯poly（butylene succinate））基聚合物及其模拟降解产物二元酸、二元醇对赤子爱胜蚓（Eisenia foetida）的存活和生长的影响。研究结果表明：48 h内二元酸、二元醇质量浓度在低于3 400 mg.L-1时对蚯蚓的存活没有影响,滤纸接触法测得丁二酸、己二酸、1,4-丁二醇、1,6-己二醇对蚯蚓的LC50分别为：3 523、3 402、74 907、18 160 mg.L-1;在自然土壤实验中,相比空白实验,蚯蚓在含有不同分子量、不同质量分数的PBS及PBS-co-HS、PBS-co-BA土壤中经过14 d的培养,体质量明显增加,且所有的蚯蚓没有任何病状或伤口出现。以上结果表明PBS基聚合物对该物种是安全的。     

The performance of nitrate-reducing Fe(II) oxidation processes under variable initial Fe/N ratios: The fate of nitrogen and iron species

•Bacterially-mediated coupled N and Fe processes examined in incubation experiments. •NO₃⁻ reduction was considerably inhibited as initial Fe/N ratio increased. •The maximum production of N₂ occurred at an initial Fe/N molar ratio of 6. •Fe minerals produced at Fe/N ratios of 1–2 were mainly easily reducible oxides. The Fe/N ratio is an important control on nitrate-reducing Fe(II) oxidation processes that occur both in the aquatic environment and in wastewater treatment systems. The response of nitrate reduction, Fe oxidation, and mineral production to different initial Fe/N molar ratios in the presence of Paracoccus denitrificans was investigated in 132 h incubation experiments. A decrease in the nitrate reduction rate at 12 h occurred as the Fe/N ratio increased. Accumulated nitrite concentration at Fe/N ratios of 2–10 peaked at 12–84 h, and then decreased continuously to less than 0.1 mmol/L at the end of incubation. N₂O emission was promoted by high Fe/N ratios. Maximum production of N₂ occurred at a Fe/N ratio of 6, in parallel with the highest mole proportion of N₂ resulting from the reduction of nitrate (81.2%). XRD analysis and sequential extraction demonstrated that the main Fe minerals obtained from Fe(II) oxidation were easily reducible oxides such as ferrihydrite (at Fe/N ratios of 1–2), and easily reducible oxides and reducible oxides (at Fe/N ratios of 3–10). The results suggest that Fe/N ratio potentially plays a critical role in regulating N₂, N₂O emissions and Fe mineral formation in nitrate-reducing Fe(II) oxidation processes.     

利用彗星实验检测丙烯酰胺对小鼠两种细胞的DNA损伤和修复

为了研究丙烯酰胺致小鼠睾丸细胞和外周血淋巴细胞DNA的损伤及修复情况,同时比较这两种细胞对丙烯酰胺的敏感性,将雄性昆明种小鼠一次性腹腔注射丙烯酰胺(50mg·kg-1(bw)),在暴露后第1、2、4、6、8、10、12d,分别对其睾丸组织细胞和外周血淋巴细胞DNA损伤进行彗星实验分析.结果表明,暴露结束后每个时间点小鼠睾丸组织细胞、外周血淋巴细胞DNA的迁移率均显著高于阴性对照组,随时间推移两种细胞DNA迁移距离逐渐降低,同一时间点睾丸组织细胞DNA损伤较外周血淋巴细胞DNA损伤更为严重,两者差异显著(p<0.05).以上结果表明,睾丸组织和外周血淋巴细胞可能是丙烯酰胺的作用位点;机体对丙烯酰胺造成的遗传损伤有一定的修复能力;与淋巴细胞相比,睾丸细胞对丙烯酰胺导致的遗传损伤更为敏感.