赤泥原料及其对吸附剂吸附性能的影响

赤泥的堆放会对环境造成污染,但其具有较高的吸附性能,因此研究制备赤泥吸附剂能达到以废治废的目的。实验分别采用平果和德保赤泥制备吸附剂,研究了赤泥原料及赤泥吸附剂的物相组成,采用除氟及除铜实验研究了赤泥产地及赤泥堆放时间对吸附剂吸附性能的影响。结果表明,以平果、德保赤泥制备的吸附剂,在焙烧温度500℃、焙烧2 h、溶液p H值为6的条件下,氟浓度可分别从19 mg/L降低到0.21、0.19 mg/L;铜浓度可分别从64 mg/L降低到0.32、0.51 mg/L。对氟的吸附容量均可达0.94 mg/g;对铜吸附容量分别可达3.18、3.17 mg/g;对氟、铜的去除率分别在99%、98%以上。     

锰渣-赤泥吸附剂制备及其对铜（Ⅱ）吸附性能

锰渣是锰矿石生产硫酸锰过程产生的酸性过滤渣,赤泥是拜耳法生产氧化铝过程产生的碱性废渣,两种废渣排放量大,综合利用程度低。以锰渣和赤泥为原料,混合焙烧制备锰渣-赤泥吸附剂,实现了两种废渣的中和,制得的吸附剂pH接近中性。研究了锰渣-赤泥吸附剂对溶液中2价铜离子的吸附性能,为废渣的综合利用提供新途径。考察了吸附时间、溶液初始铜离子质量浓度、溶液pH等条件对吸附剂吸附溶液中铜离子的影响。结果表明：不同焙烧温度制得的吸附剂对铜离子的吸附平衡时间为22 h;焙烧温度为700 ℃制得的吸附剂（A700）对铜离子的吸附效果最好,在固液质量体积比（g/L）为0.4∶1条件下,达到平衡时溶液中铜离子的质量浓度可从20 mg/L降低到0.053 mg/L,平衡吸附量为45.739 2 mg/g,对铜离子的吸附去除率达到99.72%。吸附剂A700对铜离子的吸附符合准一级动力学模型和Langmuir等温吸附模型。     

焙烧对赤泥比表面积及孔隙结构影响的研究

采用焙烧方法对赤泥进行改性,通过氮吸附、扫描电镜(SEM)、红外光谱(IR)和X射线衍射(XRD)技术分析焙烧条件对赤泥微观结构的影响,例如焙烧温度和时间,并通过铜离子吸附实验对改性赤泥(R-RM)的吸附性能做出评价.结果表明,R-RM的比表面积和平均孔容积随焙烧温度升高和时间的延长都是先增大后减小,在387 ℃/2 h条件下分别达到最大值15.7303 m2/g和0.007946 cm3/g.焙烧能够使赤泥中的碳酸盐化合物分解,提高颗粒孔隙率;使结合水蒸发,从而疏通内部孔道,降低水膜对吸附质的传质阻力.在室温下,R-RM对20 mg/L铜离子的最大吸附容量为1.89 mg/g,去除率达94.5%.     

赤泥负载铈吸附剂对废水中氟的吸附性能研究

将赤泥通过盐酸活化,得到酸活化赤泥,以酸活化赤泥为载体,氧化铈为活性组分,制备了赤泥负载铈吸附剂,在25℃和静态条件下,对赤泥负载铈吸附剂处理含氟废水进行了研究。结果表明,赤泥负载铈吸附剂的制备条件为:盐酸浓度为6 mol/L,赤泥负载铈的反应时间为16 h,四水硫酸铈的质量浓度为0.4 g/L,焙烧温度为500℃;在废水pH为6.0,氟的质量浓度为40 mg/L,吸附时间为90 min,按氟与赤泥负载铈吸附剂质量比为1:100投加赤泥负载铈吸附剂进行处理,氟的去除率可达98%以上。利用Langmuir吸附等温式对吸附数据进行拟合,得到25℃下的线性方程为(ρe/qe)/(g.L-1)=[0.016 3ρe/(mg.L-1)]+0.050 3,线性相关性R2=0.992 3,吸附剂的饱和吸附量为61.35 mg/g。氟在吸附剂表面的吸附是单分子层吸附。     

硅锰复合物的制备及其对铜的吸附性能

采用共沉淀法制备了硅锰复合物吸附剂,并对其吸附金属铜的性能进行了初步研究。用Fourier红外光谱对制备的硅锰复合物吸附剂进行了表征,探讨了吸附剂的投加量、p H、温度和震荡时间等因素对土壤中铜的吸附性能的影响。结果表明,当土壤溶液的p H为5.5、土壤溶液中铜离子的初始浓度为0.8 mmol/L,θ为25℃,震荡2 h时,土壤对铜的吸附效果最佳,最大吸附量为21.59 mg/g,吸附模型符合Freundlich吸附等温线。     

磁改性甘蔗渣对铜离子的吸附研究

以三氯化铁、氯化镍和甘蔗渣为原料制备磁改性生物质吸附材料,并以吸附率作为评价指标考察其对二价铜离子的吸附性能。实验研究了吸附剂用量、铜离子初始浓度、pH、温度以及时间对改性材料吸附效果的影响。结果表明,在Cu~(2+)初始浓度为10 mg/L,pH 7,300μL吸附剂,常温下吸附150 min,材料对铜离子的吸附率达到72%。此外,吸附材料在吸附后可通过磁性分离,实现二次利用。廉价、高效、可回收的生物质吸附剂在环境废水处理方面展现了良好的应用前景。     

赤泥对含铜废水的吸附性能研究

赤泥是氧化铝工业产生的固体废渣,由于其比表面积大,具有较好的吸附性能。本文将赤泥用于含铜废水的处理,并通过实验探索赤泥吸附含铜废水的条件。实验结果表明,赤泥吸附剂在pH值=4,投加量为6g/L,吸附时间为45min,在室温的条件下,吸附率可达到99.73%,吸附量可达90.9mg/g;进行了等温吸附模型研究,研究结果表明赤泥对Cu2+的吸附符合Langmuir吸附等温模型,Cu2+容易吸附在赤泥吸附剂的表面。本研究为工业固体废物赤泥的利用及含铜废水的处理提供了一种经济有效的途径。     

超声化学辅助法制备纳米ZnS及其对水中铜离子的吸附性能

铜污染引发的环境问题严重影响着人类的生命健康。本文以Zn(NO_3)_2·6H_2O和Na_2S·9H_2O为原料,水为溶剂,通过超声化学辅助法制备出纳米ZnS,并将其应用于水中铜离子的吸附脱除。利用FTIR、XRD、SEM和N2物理吸附等手段进行表征,研究了初始浓度、接触时间、处理温度、pH和竞争阳离子等对铜离子吸附容量的影响。结果表明,制得的纳米ZnS为单一立方相闪锌矿,颗粒呈不规则块状,孔道结构主要为纳米ZnS晶粒团聚形成的聚集孔,孔径分布较宽。该纳米ZnS表现出对水中铜离子良好的吸附性能,在吸附剂量200mg/L、铜离子初始浓度400mg/L、接触时间12h、处理温度25℃的条件下,饱和吸附容量高达629.8mg/L,水中Na~+和K~+对吸附性能无明显影响,且其对水中铜离子的脱除机理为离子交换与吸附的协同作用。     

改性赤泥颗粒吸附剂的性质及机理研究

采用焙烧法对赤泥进行活化处理,将其与粉煤灰、碳酸氢钠和膨润土按照质量比为16∶2∶1∶3制成改性赤泥颗粒,该改性赤泥颗粒破碎率与磨损率之和为0.2%。将其作为吸附剂,采用静态吸附试验方法研究了该改性赤泥颗粒吸附剂对模拟含磷废水除磷的一般规律,在磷的质量浓度为3~100 mg/L条件下,考察了反应时间、初始磷浓度、投加量等因素对改性赤泥颗粒吸附效果的影响,经过计算得出其饱和吸附量。结果表明,改性赤泥颗粒对磷的去除效果在反应8 h后趋于稳定,其最佳投加量为5 g/L,改性赤泥颗粒的饱和吸附量为56.2 mg/g。     

甲酸铜还原制备煤质活性炭CuCl吸附剂工艺研究

以煤质活性炭为载体,氯化铜为铜源,甲酸铜为还原剂,采用热分散法制备CuCl-AC吸附剂。通过变压吸附法(PSA)测量该吸附剂对乙烯乙烷吸附分离性能。考察了铜担载量、焙烧温度、焙烧时间等因素的影响。结果表明,通过甲酸铜还原法制备CuCl-AC吸附剂,最佳制备工艺条件为:CuCl_2担载量为4mmol,Cu(HCOO)_2担载量为4mmol,焙烧温度300℃,焙烧时间4 h。在30℃,0.5MPa的条件下,它对乙烯的吸附量为32.39 mL/g,分离系数为2.47,对变压吸附具有很好的分离应用前景。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.