聚硅酸铝铁絮凝剂研究进展

聚硅酸铝铁（PSAF）作为一种新型无机高分子絮凝剂,其除浊、脱色及去除有机物的性能优越,文献报道的最高去除率可分别达97％、98％、87％。使用不同方法制取的PSAF性能及稳定性有较大区别;同时,PSAF的效果还受水体参数的影响。本文介绍了PSAF的作用原理、制作方法、使用效果及其影响因素,最后简要概括了当前研究存在的问题。     

纳米SiO2在含阴离子表面活性剂低浊水处理中的应用

在含有阴离子表面活性剂-十二烷基硫酸钠(SDS)的6 NTU高岭土悬浊液中,改变SDS的浓度,投加纳米SiO2与聚合铝PAC进行动态混凝实验与静沉实验,借助图像分析技术与分形理论,探讨了纳米SiO2与PAC处理含SDS低浊水的作用机理、絮凝效果与形态学特征.结果表明:①纳米SiO2与SDS使高岭土粒子表面负电性增强.纳米SiO2的絮凝机理以吸附架桥为主.②纳米SiO2对SDS的去除效果优于PAC.SDS浓度越高,去除效果越显著.但纳米SiO2对无机高岭土粒子的处理能力不如PAC,PAC絮凝后的上清液浊度低.当SDS浓度增至10 mg/L时,纳米SiO2对SDS的去除率高,而PAC对SDS的絮凝能力弱,PAC对无机颗粒的去除效果也下降.③助凝剂纳米SiO2较强的吸附活性能加快PAC絮体成长为结构密实的RLCA构型,分维值高,絮凝效果好.     

改性秸秆-铝盐复合絮凝剂的制作与应用

以铝盐、作物秸秆为主要原料,用氢氧化钠、氯乙酸通过碱化和醚化对秸秆进行改性,在一定条件下与铝盐合成了一种新型的无机天然有机复合絮凝剂（定名为SPA）,研究了其对高岭土模拟废水的吸光度和浊度去除性能,并对几个主要影响因素作了考察。结果表明：SPA对该模拟废水有较好的处理效果,5 mL SPA/1 L高岭土悬液的投量就可以获得吸光度和浊度88%以上的去除率,室温即可达到最佳处理效果,且pH值适应范围广,大约为3～9。还进行了SPA和铝盐对市政污水的处理效果的对比分析,试验结果表明：对其出水的吸光度去除率、浊度去除率和SS去除率来说,SPA都比铝盐的处理效果好;SPA对COD的去除效果比铝盐略差,但是在低投量时其COD去除率为65%,可以满足污水初级处理的要求。     

电解铝工程清洁生产分析与评价

本文以乐山某铝业有限公司新建10万吨电解铝工程为例,简述了电解铝生产工艺,重点对电解铝工程的清洁生产进行分析。从生产工艺的先进性、污染物排放量少、清洁原料、原辅材料消耗低、节能措施和废物回收利用等方面对预焙阳极电解槽技术的清洁生产进行分析。通过清洁生产指标分析结果,乐山某铝业有限公司电解铝工程满足清洁生产标准要求,经预焙槽技术和自焙槽相比,预焙槽技术具有污染物排放量少,物耗能耗低,使用原辅料清洁,电流效率高的特点,以不同预焙槽原辅材料消耗量回归分析结果及其综合分析,大型预焙阳极电解槽技术是铝电解行业的清洁生产工艺。     

An investigation on the dust explosion of micron and nano scale aluminium particles

A series of dust explosion were conducted to compare the flame structure between nano and micron aluminium dusts. Two-color pyrometer technique is applied to have qualitative observation of flame development. Measurement of temperature indicates that explosion in micron aluminium dust clouds start in a single spot at 3000 K, in contrast, explosion in nano aluminium dust clouds start when hot powder accumulated to a certain amount at lower temperature of 2600 K. For micron aluminium dust clouds, flame at leading edge has the highest temperature and propagates in all directions. On the other hand, flame in nano aluminium dust clouds propagate only upward with the hottest part left behind at the downside. As flame propagates, the temperature at top edge gradually decreases from 2600 K to finally 2000 K, but temperature at bottom edge maintains in 3000 K with no significant displacement. The unevenness of flame structure is considered as the consequence of different particle densities, which suggests that the reaction of nano aluminium particles stays in molten state, meanwhile, the high surface area also leads to unignorable heat loss.     

改性与成型层状氢氧化镁铝对不同水体中PO43- 的脱除性能

利用大型工业设备制备出性能稳定的粉末层状氢氧化镁铝(500 kg.批-1,记为Mg-Al LDH),采用沉积法将Mg-Al LDH进行改性与成型,研究了改性与成型层状氢氧化镁铝(记为MG Mg-Al CLDH)对水溶液、废水、不同地带海水中PO34-的动态吸附脱除及再生性能.结果表明,MG Mg-Al CLDH能够有效脱除不同水体中的PO34-,满足污水综合排放一级标准或海水水质一级标准.MG Mg-Al CLDH对PO34-脱除主要是通过离子交换和"结构记忆"效应共同实现的.MG Mg-Al CLDH对水溶液中PO34-的穿透吸附量是未改性时的6倍以上,再生率为126.24%,PO34-的穿透曲线受固定床高度、流量、溶液初始浓度、溶液初始pH值的影响,液膜扩散是吸附过程的主控步骤.当溶液初始浓度低至4.61 mg.L-1时,MG Mg-Al CLDH能将某污水处理厂二级出水中PO34-有效脱除,满足污水综合排放一级标准.当PO34-浓度低至0.38μmol.L-1,MG Mg-Al CLDH仍能将其从海水中有效脱除,达到海水水质一级标准,为解决Mg-Al LDH在实际应用中存在粉末易堵塞床体、无法实现固液分离和再生的问题及水体中磷的脱除提供了一条新型可行之路.     

多孔不锈钢基氧化铝膜去除水溶液中的Cr(VI)和Cd(II)

通过悬浮粒子浸涂法将合成的γ-Al₂O₃纳米粒子固载于316L多孔不锈钢表面以吸附水溶液中的Cr（VI）和Cd（Ⅱ）.扫描电镜（SEM）和X射线衍射（XRD）测试结果表明,γ相的Al₂O₃纳米粒子均匀地涂在了316L多孔不锈钢基体上,膜体表面沉积厚度约为20 μm.该膜对单一Cr（VI）和Cd（Ⅱ）吸附的最佳pH分别为3.0~4.0和8.0~9.0,吸附均符合动力学准二级模型和Langmuir吸附等温模型,最大吸附量分别为0.603 mg·g^-1和0.399 mg·g^-1.本研究可为水体中的高毒性重金属Cr（VI）和Cd（Ⅱ）去除提供一定的理论和技术参考.     

三种化合物浸泡处理对石棉晶格结构和表面电荷的影响

为了研究经柠檬酸铝、混合稀土或亚硒酸钠浸泡处理温石棉对温石棉晶格结构和表面电荷的影响,用不同浓度的柠檬酸铝、混合稀土或亚硒酸钠溶液浸泡温石棉1小时后,通过透射电镜测定其衍射环直径的大小,分析石棉晶格结构的改变,并利用石棉纤维吸附亚甲蓝能力的测定方法,分析温石棉表面电荷。结果显示,用三种化合物处理石棉后,其衍射环直径均增大,而且用三种化合物处理后的石棉对亚甲蓝的吸附能力均明显降低,并且随着化合物剂量的增加其降低愈明显。上述结果表明,用三种化合物处理石棉,均可改变石棉的晶格结构,且可能减少其表面电荷。     

Bacterial reduction and release of adsorbed arsenate on Fe(Ⅲ)-, Al- and coprecipitated Fe(Ⅲ)/Al-hydroxides

Mobilization of arsenic under anaerobic conditions is of great concern in arsenic contaminated soils and sediments. Bacterial reduction of As(V) and Fe(Ⅲ) influences the cycling and partitioning of arsenic between solid and aqueous phase. We investigated the impact of bacterially mediated reductions of Fe(Ⅲ)/Al hydroxides-bound arsenic(V) and iron(Ⅲ) oxides on arsenic release. Our results suggested that As(V) reduction occurred prior to Fe(Ⅲ) reduction, and Fe(Ⅲ) reduction did not enhance the release of arsenic. Instead, Fe(Ⅲ) hydroxides retained their dissolved concentrations during the experimental process, even though the new iron mineral-magnetite formed. In contrast, the release of reduced As(Ⅲ) was promoted greatly when aluminum hydroxides was incorporated. Thus, the substitution of aluminum hydroxides may be responsible for the release of arsenic in the contaminated soils and sediments, since aluminum substitution of Fe(Ⅲ) hydroxides universally occurs under natural conditions.     

Protective effect of Spirulina platensis against aluminium-induced nephrotoxicity and DNA damage in rats

The protective effect of Spirulina platensis (SP) powder against aluminium-induced nephrotoxicity and DNA damage in rats was studied. Male rats receiving daily 40 mg/kg b.wt. aluminium chloride (AlCl₃) orally had increased serum levels of urea and creatinine, up regulated kidney injury molecule-1 and tissue inhibitor of metalloproteinase-1 genes, down regulated catalase and glutathione peroxidase genes, and increased all parameters of kidney DNA damage using comet assay. Treatment with SP alleviated all AlCl₃-induced effects of toxicity, especially when the animals were pre-treated.