中性盐对胶原与铬和铝反应的影响

通过测定NaCl和Na2SO4对Cr(Ⅲ)和Al(Ⅲ)在胶原纤维上的结合量的影响及观察胶原分子在这两种中性盐存在时的聚集行为,初步揭示了NaCl和Na2SO4对胶原-铬和胶原-铝反应的影响规律。实验结果表明,NaCl可以通过破坏胶原表面的水膜,促进胶原聚集,从而有利于胶原与金属鞣剂的反应,使金属鞣剂在胶原上的结合量增加;Na2SO4也会促进胶原聚集,但由于SO42-对金属鞣剂产生了较强的蒙囿作用,整体上表现为削弱了胶原与金属鞣剂的反应。     

多金属配合鞣剂的特性及其在中高档革上的应用

本文简要地用配合物的价键理论和配位场理论解释了Cr~(3 )、Zr~( 4)、Al~(3 )、Ti~(4 )Fe~( 3)、RE~(3 )等配合鞣剂的鞣性差异;论述了Cr—Zr—Al多金属配合鞣剂的实质、特性、适用范围、使用方法和应用多金属配合鞣剂的经济效益和社会效益。     

水杨酸-金属配合物的合成及其鞣制性能

选用低毒、弱鞣性的水杨酸和3种金属盐(CrCl3、AlCl3、CuCl2)进行试验,目的是通过2种弱鞣性的物质进行结合鞣,观察其鞣制效果。首先合成配合物,即Rigid Matrix,然后对配合物进行结构分析,确定其分子结构,得到n(Cr)∶n(Sa)、n(Al)∶n(Sa)、n(Cu)∶n(Sa)分别为3∶1、3∶1、2∶1的比例形成配合物。最后用其来进行鞣制皮粉,并通过DSC测定鞣后皮粉的相变温度,来预测水杨酸-金属配合物的鞣制性能。试验发现:水杨酸铬鞣制皮粉的Onset点为146.7℃、水杨酸铝为145.7℃、水杨酸铜为144.1℃。     

用GFC法研究柠檬酸盐蒙囿铝(Ⅲ)配合物的组成分布

通过凝胶过滤色谱 (GFC)对柠檬酸盐 (Cit)蒙囿的铝 (Ⅲ )配合物溶液的组分进行分离 ,用低压离子色谱(LPIC)和铬天青比色法分别测量各组分中Cit和Al3 +的含量 ,进而对溶液中各组分的分布及各组分中[Al3 +]/[Cit]值进行分析 ,为推断铝配合物的结构和Cit参与配位的方式提供了依据。     

食品中铝含量检测优化技术体系研究

目的建立高效的测定食品中总铝和可溶性铝的测定方法。方法采用微波消解法(HNO_3、HNO_3+H_2SO_4、HNO_3+HF)与湿法消解法(HNO_3、HNO_3+H_2SO_4)进行样品前处理,在铬天青S分光光度法和电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectrometry,ICP-OES)下测定标准参考物质与普通样品铝含量,同时用添加回收实验验证方法的可靠性与准确性。结果采用微波消解法(HNO_3+HF)-优化铬天青S分光光度法和微波消解法(HNO_3+HF)-ICP-OES时,标准参考物质的铝含量测定结果在标准参考值范围内,这2种方法的加标回收率为86.5%~101.1%;采用微波消解(HNO_3)-ICP-OES法、微波消解(HNO_3)-铬天青S分光光度法与湿法消解(HNO_3+H_2SO_4)-铬天青S分光光度法时,测得普通样品的标准偏差为0.50~4.22 mg/kg,加标回收率为74.3%~99.0%。结论微波消解法(HNO_3+HF)-优化铬天青S分光光度法和微波消解法(HNO_3+HF)-ICP-OES法,均可准确测得总铝含量;微波消解(HNO_3)-ICP-OES法、微波消解(HNO_3)-铬天青S分光光度法与湿法消解(HNO_3+H_2SO_4)-铬天青S分光光度法测得的结果是可溶性铝。     

从价键理论到协同单元理论鞣制机理的发展

价键理论根据鞣剂与胶原活性基团形成配位键的强弱 ,解释各种无机鞣剂鞣革性能的差异。价键理论认为 :Cr( )与 Al( )相比 ,由于 Cr( )形成的配合物是内轨型配合物 ,而 Al( )形成的配合物是外轨型配合物 ,因此铬配合物更稳定 ,Cr( )鞣革比 Al( )鞣革耐湿热稳定性好 ,收缩温度高 ;革收缩时配位键发生断裂。但对收缩过程的热力学研究发现 ,胶原或革收缩时配位键并未断裂 ,而是氢键破坏 ,收缩温度与收缩反应的活化能有关。因此协同单元理论认为 :革收缩过程是一个动力学过程 ;收缩温度与协同单元的大小有关。协同单元理论对各种鞣剂的鞣性差异给出了比较满意的解释。     

氧化多糖-铝锆配合物鞣制技术的综合评价

选用羧基含量和相对分子质量不同的氧化多糖配体OP1和OP2与铝盐、锆盐(AZ)进行配位鞣制,并与传统柠檬酸-铝锆(CA-AZ)鞣制和铬(Cr)鞣进行对比,评估了4种鞣制技术的鞣革性能、坯革性能和污染负荷。结果表明配体的相对分子质量对鞣制性能的影响比羧基含量大。重均相对分子质量7000左右的OP2同AZ形成的配合物鞣革收缩温度高(82.1℃)、阳电性强(等电点高于7.0),对染整材料的吸收率好(高于80%),使得坯革物性优良,仅次于铬坯革。相对分子质量较低的OP1(Mm;1000左右)和CA同AZ的配位鞣制性能不及OP2。此外,OP2-AZ鞣制废水的生物降解性优于CA-AZ和铬鞣废水。因此,氧化多糖-铝锆配合物鞣制技术有望成为一种实用、清洁的无铬皮革制造技术。     

回湿液中铬配合物的组成研究

为了解释回湿过程中,铬配合物从皮胶原中脱落的原因,以硫酸铬鞣制皮粉,鞣制皮粉干燥后,用0.2%甲酸和200%水回湿,得到回湿液。使用离子交换色谱对回湿液中的铬配合物进行分离;利用紫外-可见光谱和红外光谱对铬配合物进行分析。结果表明:湿液由+1、+2、+3、+4和+5价的铬配合物组成,其中高阳电性组分(+3、+4和+5价)含量为77.22%,是铬配合物的主要组分。回湿液中配体与中心离子之间形成桥键的数目较少,配合物体积较小。配体与中心离子之间主要以单点配位的方式相互结合,这种不稳定的配位方式,是造成铬配合物从皮胶原中脱落的主要原因。     

不同有机配体对锆-铝-钛多金属配合鞣液反应性的影响

在不同有机配体(柠檬酸、乳酸、邻苯二甲酸、甲酸和双醛淀粉)、pH以及熟化时间的条件下,用pH电位滴定法对锆-铝-钛多金属配合鞣液的稳定性进行了研究,然后进行配体两两配伍,用pH电位滴定法和紫外吸收光谱等对锆-铝-钛多金属配合鞣液的稳定性进行了表征,得到最佳配伍方案,最后通过鞣制工艺对锆-铝-钛多金属配合鞣液的反应性进行了表征。结果表明:当鞣液中各金属离子摩尔比为n(Ti4+)∶n(Al3+)∶n(Zr4+)=0.5∶4∶1,且n(金属离子)∶n(柠檬酸)∶n(乳酸)=1∶0.1∶0.1时,配合物在稳定性和反应性两方面的表现最好,鞣制革样的收缩温度可达92℃。     

锆-铝-钛多金属配合物溶液的制备

通过对锆、铝、钛和蒙囿剂的混合液浑浊pH值、D-λ曲线的研究,确定了具有具有较高浑浊pH值的锆-铝-钛多金属配合物溶液的配比摩尔比为n(Ti4 )∶n(Al3 )∶n(Zr4 )=0.5∶4∶1,n(金属离子)∶n(柠檬酸)=1∶0.2,熟化时间大于24 h。     

硫酸铝对铬液碱度的影响及Cr-Al鞣液碱度的确定

在配制铬铝鞣液时 ,由于硫酸铝的强烈水解作用会导致铬铝鞣液表观碱度的显著降低 ,试验和公式推导都证明降低值与铝铬比成线形关系。首次推导出计算铬铝鞣液碱度的简便计算公式 ,并通过碱度的关联性将铬铝鞣液与铬鞣液的重要参数联系起来 ,简化了铬铝鞣液的配制。     

Fe2（SO4）3/γ-Al2O3固体酸催化剂制备条件的优化

采用浸渍法制备Fe2(SO4)3/γ-Al2O3固体酸催化剂,于常压下利用Fe2(SO4)3/γ-Al2O3催化水解菲丁制备肌醇,并以肌醇收率表征催化剂活性强度。考察浸渍质量浓度、浸渍时间、焙烤温度对催化剂活性的影响,采用响应面法进行优化,得到制备Fe2(SO4)3/γ-Al2O3最佳条件:浸渍质量浓度50mg/mL、浸渍时间4h、焙烧温度436℃,在此条件下制备的Fe2(SO4)3/γ-Al2O3固体酸催化剂催化水解菲丁,肌醇收率为14.18%,菲丁水解效率为70.9%。     

Formation of layered Fe(II)-Al(III)-hydroxides during reaction of Fe(II) with aluminum oxide

The reactivity of aqueous Fe(II) with aluminum oxide in anoxic solutions was investigated with batch kinetic experiments combined with Fe K edge X-ray absorption spectroscopy measurements to characterize Fe(II) sorption products. Formation of Fe(II)-Al(III)-layered double hydroxides with an octahedral sheet structure similar to nikischerite (NaFe(II)(6) Al(3)(SO(4))(2)(OH)(18) (H(2)O)(12)) was observed within a few hours during sorption at pH 7.5 and aqueous Fe(II) concentrations of 1-3 mM. These Fe(II) phases are composed of brucite-like Fe(II)(OH)(2) sheets with partial substitution of Al(III) for Fe(II), charge balanced by anions coordinated along the basal planes. Their fast rate of formation suggests that these previously unrecognized Fe(II) phases, which are structurally and compositionally similar to green rust, may be an important sink of Fe(II) in suboxic and anoxic geochemical environments, and impact the fate of structurally compatible trace metals, such as Co(II), Ni(II), and Zn(II), as well as redox-reactive species including Cr(VI) and U(VI). Further studies are required to assess the thermodynamics, formation kinetics, and stability of these Fe(II) minerals under field conditions.     

结晶添加剂对硫酸钾结晶过程影响研究

本文研究了NH+ 4 、K+ 、Cl-、SO2 -4离子的混合体系中K2 SO4晶习、晶形特性 ,考查了不同结晶添加剂对K2 SO4结晶的影响 ,探讨了各种离子对硫酸钾在混合体系中结晶过程影响机制。试验结果表明 ,Mg2 + 和十二烷基苯磺酸钠有促进K2 SO4晶体结晶作用 ,而Fe3 + 、Al3 + 对结晶有一定的抑制作用     

中段废水仿酶处理的研究

铁与羧酸形成的螯合物（Fe-CA）不仅性能稳定,价格低廉,而且在功能上能较好地模拟木素过氧化物酶.中试结果显示,应用Fe-CA处理系统可以很好的处理木素含量较高的制浆造纸中段废水,COD去除率可达65%.其优化条件为：Fe-CA用量10g/m^3,过氧化氢用量150g/m%^3,硫酸铝投加量为400g/m^3,APAM加入量为5g/m^3,处理时间30min,沉降时间6h.     

聚硅硫酸铝混凝性能的研究

以硫酸铝、硅酸钠为原料合成了具有不同 Al3+ /SiO2摩尔比的聚硅硫酸铝( PASS)混凝剂.通过对造纸废水的混凝实验,确定了 PASS 的 Al3+ /SiO2最佳配比为 1/1和适用 pH值范围为 5～ 11,与硫酸铝的混凝对比实验表明 PASS具有更好的处理效果.同时,对 PASS的混凝机理进行了分析、探讨.     

Simultaneous application of dissolution/precipitation and surface complexation/surface precipitation modeling to contaminant leaching

This paper discusses the modeling of anion and cation leaching from complex matrixes such as weathered steel slag. The novelty of the method is its simultaneous application of the theoretical models for solubility, competitive sorption, and surface precipitation phenomena to a complex system. Selective chemical extractions, pH dependent leaching experiments, and geochemical modeling were used to investigate the thermodynamic equilibrium of 12 ions (As, Ca, Cr, Ba, SO4, Mg, Cd, Cu, Mo, Pb, V, and Zn) with aqueous complexes, soluble solids, and sorptive surfaces in the presence of 12 background analytes (Al, Cl, Co, Fe, K, Mn, Na, Ni, Hg, NO3, CO3, and Ba). Modeling results show that surface complexation and surface precipitation reactions limit the aqueous concentrations of Cd, Zn, and Pb in an environment where Ca, Mg, Si, and CO3 dissolve from soluble solids and compete for sorption sites. The leaching of SO4, Cr, As, Si, Ca, and Mg appears to be controlled by corresponding soluble solids.     

生物法脱墨废水污染负荷及其混凝处理

研究了生物法脱墨废水污染负荷,分别用不同的混凝剂Al2(SO4)3、PAC与PAM配合对该废水进行处理,确定处理该废水的最佳工艺条件,并在相同条件下与化学法脱墨废水的处理效果作比较.结果表明,生物法脱墨废水比化学法脱墨废水污染负荷低且易处理;PAC与PAM配合使用处理效果优于Al2(SO4)3与PAM配合使用处理效果,其对生物法脱墨废水CODCr去除率最高可达79.1%,处理后CODCr为81 mg/L,其浊度接近普通自来水.     

Density functional theory studies on the structures and water-exchange reactions of aqueous Al(III)-oxalate complexes

The structures and water-exchange reactions of aqueous aluminum-oxalate complexes are investigated using density functional theory. The present work includes (1) The structures of Al(C(2)O(4))(H(2)O)(4)(+) and Al(C(2)O(4))(2)(H(2)O)(2)(-) were optimized at the level of B3LYP/6-311+G(d,p). The geometries obtained suggest that the Al-OH(2) bond lengths trans to C(2)O(4)(2-) ligand in Al(C(2)O(4))(H(2)O)(4)(+) are much longer than the Al-OH(2) bond lengths cis to C(2)O(4)(2-). For Al(C(2)O(4))(2)(H(2)O)(2)(-), the close energies between cis and trans isomers imply the coexistence in aqueous solution. The (27)Al NMR and (13)C NMR chemical shifts computed with the consideration of sufficient solvent effect using HF GIAO method and 6-311+G(d,p) basis set are in agreement with the experimental values available, indicating the appropriateness of the applied models; (2) The water-exchange reactions of Al(III)-oxalate complexes were simulated at the same computational level. The results show that water exchange proceeds via dissociative pathway and the activation energy barriers are sensitive to the solvent effect. The energy barriers obtained indicate that the coordinated H(2)O cis to C(2)O(4)(2-) in Al(C(2)O(4))(H(2)O)(4)(+) is more labile than trans H(2)O. The water-exchange rate constants (k(ex)) of trans- and cis-Al(C(2)O(4))(2)(H(2)O)(2)(-) were estimated by four methods and their respective characteristics were explored; (3) The significance of the study on the aqueous aluminum-oxalate complexes to environmental chemistry is discussed. The influences of ubiquitous organic ligands in environment on aluminum chemistry behavior can be elucidated by extending this study to a series of Al(III)-organic system.     

Chemical response of lakes in the Adirondack Region of New York to declines in acidic deposition

Long-term changes in the chemistry of wet deposition and lake water were investigated in the Adirondack Region of New York. Marked decreases in concentrations of SO4(2-) and H+ in wet deposition have occurred at two sites since the late 1970s. These decreases are consistent with long-term declines in emissions of sulfur dioxide (SO2) in the eastern United States. Changes in wet NO3- deposition and nitrogen oxides (NOx) emissions have been minor over the same interval. Virtually all Adirondack Lakes have shown marked decreases in concentrations of SO4(2-), which coincide with decreases in atmospheric S deposition. Concentrations of NO3- have also decreased in several Adirondack lakes. As atmospheric N deposition has not changed over this period, the mechanism contributing to this apparent increase in lake/watershed N retention is not evident. Decreases in concentrations of SO4(2-) + NO3- have resulted in increases in acid-neutralizing capacity (ANC) and pH and resulted in a shift in the speciation of monomeric Al from toxic inorganic species toward less toxic organic forms in some lakes. Nevertheless, many lakes continue to exhibit pH values and concentrations of inorganic monomeric Al that are critical to aquatic biota. Extrapolation of rates of ANC increase suggests that the time frame of chemical recovery of Adirondack Lakes will be several decades if current decreases in acidic deposition are maintained.