均苯四甲酸酐修饰壳聚糖微球对Pb2+和Cd2+的吸附

用交联的壳聚糖微球(CTS)与均苯四甲酸酐在无水条件下反应,合成了均苯四甲酸酐修饰壳聚糖微球. 用FT-IR和XPS表征了产物的结构,考察了它对水溶液中Pb2+和Cd2+的吸附行为及其影响因素. 结果表明,吸附等温线符合Langmuir方程. 当pH=5.0时,对Pb2+和Cd2+的最大吸附量分别为296.7和149.9 mg/g. 用二级吸附动力学模拟动力学过程有很好的线性相关性,据此确定为化学吸附过程. 以0.2 mol/L的EDTA为解吸剂,Pb2+和Cd2+的再生率分别为92.4%和85.3%.     

富羧类吸附树脂对BIT生产废水中有机物的吸附研究

在氯甲基化的苯乙烯-二乙烯苯聚合物的基体上,经后交联并分别辅以邻苯二甲酸(ZT1)、偏苯三甲酸酐(ZT2)、均苯四甲酸酐(ZT3)等物质进行修饰调节,自制了富羧类吸附树脂,以期达到对邻氨基苯甲酸(OABA)、1,2-苯并异噻唑-3-酮(BIT)等具有高吸附容量、易脱附的目的,并对温度、p H值等吸附影响因素进行实验,得到较好的吸附条件,采用固定床吸附工艺,确定了流速、吸附床体积数、脱附温度、吸附稳定性等参数。     

高效液相色谱法测定粗苯均四甲酸二酐中苯均四甲酸含量

将粗苯均四甲酸二酐(PMDA)样品与甲醇回流2 h,冷却后用甲醇将甲醇回流液稀释至100mL,分取20μL进样,用高效液相色谱法测定其中苯均四甲酸含量。采用的色谱柱为AgilentRP18柱(4.6mm×200 mm,10μm),流动相为磷酸(0.1+99.9)溶液与甲醇以体积比为80比20组成的混合溶液,流量为1.0mL·min~(-1),紫外检测波长为220 nm。在此条件下,粗苯均四甲酸二酐中共存的4种组分,苯均四甲酸二酐酯化产物、1,2,4-苯三甲酸酐、邻苯二甲酸、苯均四甲酸可得到有效分离。     

均苯型聚酰亚胺模塑粉的制备与性能

用含有扭曲非共平面结构的二胺1,3-二(3-氨基苯氧基-4'-苯酰基 )苯(BABB)与均苯四甲酸二酐(PMDA)缩聚制备了具有3种不同分子量的均苯型热塑性聚酰亚胺模塑粉, 并研究了其组成、 聚集态结构、 熔体黏度、 稳定性和热性能, 将模塑粉模压成型后进行机械性能测试. 结果表明, 引入柔性的二胺, 模塑粉的玻璃化转变温度(T_g)与传统的均苯型聚酰亚胺相比明显下降, 熔体黏度大幅度下降, 且具有良好的熔体黏度稳定性. 同时, 均苯四甲酸酐的存在保证了该模塑粉具有优异的热稳定性和优异的机械性能及较低的吸水率.     

均苯四甲酸酐修饰壳聚糖微球对Pb2+和Cd2+的吸附

用交联的壳聚糖微球 (CTS) 与均苯四甲酸酐在无水条件下反应,合成均苯四甲酸酐修饰壳聚糖微球,并用FT-IR和XPS表征产物的结构。研究它对水溶液中Pb2+和Cd2+的吸附行为。考察溶液的pH,吸附时间及Pb2+和Cd2+的初始浓度对吸附金属离子的影响。吸附等温线可以用Langmuir 方程较好的描述,当pH 5.0时,该吸附剂对Pb2+和Cd2+的最大吸附量分别为296.7mg g-1和149.9mg g-1。动力学过程用二级吸附动力学模拟具有很好的线性相关性,从而确定了吸附过程为化学吸附。采用0.2mol L-1的EDTA为解析剂,Pb2+和Cd2+分别获得92.4%和85.3%的解析率。表明该吸附剂有再生性能。应用于电镀废水中铅的处理,结果满意。     

改性花生壳对Cu2+的吸附

以农林废弃物花生壳作为吸附剂对废水中的Cu2+进行吸附.结果表明,花生壳的最佳改性方法为KMnO4改性法.在50mLCu2+浓度为10mg/L的水样中,改性花生壳的最佳吸附条件为:298K下投加4mesh筛上改性花生壳0.8g,pH=5,吸附75min,此时改性花生壳对Cu2+吸附率高达96.80％.KMnO4改性花生壳对Cu2+的吸附以Langmuir方程拟合更佳.     

基于三蝶烯架构的固有微孔聚酰亚胺网络的制备及其吸附特性

通过三氨基三蝶烯与3,4,9,10-苝四羧酸酐(PTCDA)、均苯四甲酸酐(PMDA)、3,3’,4,4’-联苯二酐(BPDA)以及螺环二酐(SBIDA)的缩聚反应分别合成了4种固有微孔聚酰亚胺材料(Trip-PIMs)。采用傅里叶红外光谱(FT-IR)、固体核磁碳谱(Solid-state 13C-NMR)、扫描电子显微镜(SEM)、热重分析(TG)和氮气吸附等测试手段表征了材料的微孔结构和物理化学性能,测试了材料对有机气体和液体的吸附性能。结果表明:三蝶烯结构的引入使材料获得了较高的比表面积,同时具有良好的溶胀特性;对比烷烃,该材料对胺类和苯类具有更高的吸附率;螺环结构的引入能进一步提高材料骨架的溶胀特性,从而提升材料的吸附能力。     

分子印迹复合膜对降糖药的拉曼光谱快速检测

基于分子印迹技术的特异性识别特点, 以假模板盐酸胍和4-(2-氨乙基)苯磺酰胺制备了2种分子印迹复合膜, 用其对保健品中的二甲双胍、 苯乙双胍和格列本脲进行吸附后, 采用拉曼光谱法实现了保健品中降糖药的富集与快速检测. 考察了膜制备过程中纳米银的加入对拉曼光谱的增强作用, 以及吸附样品浓度等的影响. 实验结果表明, 盐酸胍分子印迹复合膜吸附5 mg/mL以上的二甲双胍或苯乙双胍后具有明显的拉曼响应, 4-(2-氨乙基)苯磺酰胺印迹膜吸附10 mg/mL格列本脲后具有明显的拉曼响应. 所建立的分子印迹复合膜结合拉曼光谱检测方法可用于多种实际样品的检测.     

巯基膨润土的制备工艺及性能

为了简化巯基膨润土(Bent-SH)的制备工艺、降低制备成本以便于实际应用,用3-巯丙基三甲氧基硅烷(MPS)与硅酸钠协同改性膨润土(Bent)。 优化了Bent-SH的工艺条件、表征了Bent-SH的结构、测定了Bent-SH的性能。 最佳制备工艺为:Bent与MPS的用量比为1∶0.05(g/mL);m(Na₂SiO₃)∶m(Bent)=7.0∶100;固液比为1∶20(g/mL);改性悬浮液的最佳pH值为8.0～10.0;改性时间为5～6 h,反应温度为室温。 Bent-SH较Bent胶质价、膨胀倍和阳离子交换容量均有所下降,但Bent-SH对镉的饱和吸附容量为20.86 mg/g,比Bent提高了20多倍。 硅酸钠和MPS协同改性没有改变Bent层状结构,而显著增强了Bent-SH的疏水性,分散性及对镉的吸附容量和吸附选择性。 Bent-SH是一种具有应用前景的重金属污染土壤的钝化剂。     

热解吸/化学发光联用技术检测空气中痕量苯

自组装一种新型的热解吸/化学发光的仪器系统,据此建立了一种测定空气中痕量苯的新方法,并对比研究了不同吸附剂对苯的吸附性能.实验表明,Tenax-TA(2,6-二苯基对苯醚的多孔聚合物)对空气中低浓度的苯具有较好吸附效果.当从吸附剂解吸的苯蒸汽通过氧化钇(Y2O3)粉体表面时,其催化发光强度与苯浓度在相当宽的范围内呈良好的线性关系,其线性范围为0.44～44 mg/m3(r=0.9991,n=9),检出限为0.1 mg/m3(S/N=3); 对浓度为0.44 mg/m3的苯气体平行测定了9次,其相对标准偏差为4.45%;Tenax-GR(2,6-二苯并呋喃聚合物树脂加上30%石墨碳)对低浓度苯的吸附效果更好,其线性范围为0.22～22 mg/m3(r=0.9922,n=9); 检出限为0.07 mg/m3(S/N=3).本方法耗时短、简便快速,成功实现了对苯的实时在线检测.     

Graft copolymerization of epichlorohydrin and ethylenediamine onto cellulose derived from agricultural by-products for adsorption of Pb(II) in aqueous solution

In order to develop a low-cost and high efficient absorbent, cellulose was extracted from peanut hulls, soybean shells and grapefruit peels using 17.5 % NaOH and then copolymerized with epichlorohydrin and ethylenediamine. Infrared spectra and N contents show that the cellulose was copolymerized successfully with the ethylenediamine. Factors affecting the adsorption behavior of Pb(II), such as pH, temperature, ratio of solid to liquid, competitive sorption of various metal ions, initial metal concentration and adsorption time, were then investigated. The adsorption equilibrium could be obtained within 120 min and the kinetic adsorption processes fitted well with the pseudo-second order kinetic model. The isotherm adsorption data fitted well with Langmuir adsorption model and the maximum absorption capacities of the modified peanut hulls, soybean shells and grapefruit peels were 47.8, 101 and 232 mg g^?1, respectively. The competitive adsorption of mixed metal ions demonstrated that Pb(II) was preferentially removed from solution by the modified peanuts shells, soybean shells and grapefruit peels, then Cu(II) and Cr(III). Desorption of Pb(II) from modified peanut hulls, soybean shells and grapefruit peels was effectively achieved in a 1 mol L^?1 HCl solution. Ethylenediamine-modified grapefruit peels exhibited higher absorption performance than the ethylenediamine-modified soybean shells and peanut hulls and can be used as potential low-cost and high efficient absorbents for the removal of lead ions from wastewater.     

Facile fabrication of hybrid nanoparticles surface grafted with multi‐responsive polymer brushes via block copolymer micellization and self‐catalyzed core gelation

Poly(2‐(dimethylamino)ethyl methacrylate)‐b‐poly(γ‐methacryloxypropyl‐trimethoxysilane) (PDMA‐b‐PMPS) was synthesized via consecutive reversible addition‐fragmentation chain transfer (RAFT) polymerizations in 1,4‐dioxane. Subsequent micellization of the obtained amphiphilic diblock polymer in aqueous solution led to the formation of nanoparticles consisting of hydrophobic PMPS cores and well‐solvated PDMA shells. Containing tertiary amine residues, PDMA blocks in micelle coronas can spontaneously catalyze the sol–gel reactions of trimethoxysilyl groups within PMPS cores, leading to the formation of hybrid nanoparticles coated with PDMA brushes. Transmission electron microscopy (TEM) and laser light scattering (LLS) revealed the presence of monodisperse spherical hybrid nanoparticles, and the grafting density of PDMA chains at the surface of nanoparticle cores was estimated to be ～5.8 nm²/chain. PDMA brushes exhibit dual stimuli‐responsiveness, and the swelling/collapse of them can be finely tuned with solution pH and temperatures. The obtained multi‐responsive hybrid nanoparticles might find potential applications in fields such as smart devices, recyclable catalysts, and intelligent nanocarriers for drug delivery or gene transfection. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2379–2389, 2008     

响应面法优化巴旦木壳对废水中Pb、Cu和Cd的吸附及同时测定

研究废弃巴旦木壳对模拟废水中Pb、Cu和Cd的去除率。在单因素实验的基础上,采用响应面法对吸附剂投加量、吸附时间和pH值3因素进行优化。实验结果表明,Pb、Cu和Cd分别在最佳吸附吸附剂投加量0.4 g,吸附时间49.38 min,pH值为9.96;吸附剂投加量0.4 g,吸附时间49.91 min,pH值为10.13;吸附剂投加量0.4 g、吸附时间49.83 min、pH值为10.42的条件下,去除率分别为87.42%、73.49%和85.11%。采用偏最小二乘法(PLS)对Pb、Cu和Cd模拟混合试样吸附后的溶液测定的曲线进行拟合回归,计算得出吸附剂对Pb、Cu和Cd的去除率分别为83.2%、66.0%和83.3%。用PLS对吸附后的模拟废水样品进行计算分析,并间接得出巴旦木壳对Pb、Cd和Cu的去除率和建立Pb、Cd、Cu三组分同时测定的多元校正分析方法。     

A combined experimental and DFT investigation of the adsorption of humic acid by-products on polypyrrole

This study sheds light on the removal of humic acid by-products (trimellitic and pyromellitic acids; TMA and PMA, respectively) from aqueous solution using conducting polypyrrole (PPy) as an effective adsorbent. The effects of experimental factors including contact time, solution pH, initial concentration, adsorbent dose, and temperature were systematically investigated. The pseudo-second-order kinetic model provides the best correlation with adsorption experimental data. The equilibrium adsorption was well described by the Langmuir model with maximum mono-layer adsorption capacities of 47.62 and 71.43?mg?g^?1 for TMA and PMA, respectively. The analysis of thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. In addition, we investigated the adsorption mechanism using the density functional theory (DFT) calculations. The TMA and PMA were physisorbed on the PPy surface through the formation of hydrogen bonds between carboxylic groups of adsorbate molecules and the amino group of the adsorbent. The calculated theoretical data were in good agreement with experiments.     

The removal and kinetic study of Mn,Fe, Ni and Cu ions from wastewater onto activated carbon from coconut shells

Activated carbon from coconut shells (ACCS) was synthesised and used for the removal of metal ions (manganese, iron, nickel and copper) from aqueous solutions. Two different adsorption models were used for analysing the data. Adsorption capacities were determined: copper ions exhibited the greatest adsorption on activated carbon obtained from coconut shells because of their size and pH conditions. Adsorption capacity varied as a function of the pH. Adsorption isotherms from aqueous solutions of heavy metals on ACCS were determined and were found to be consistent with Langmuir’s adsorption model. Adsorbent quantity and immersion enthalpy were studied. The results were compared with other adsorbents used in a prior study.     

响应面法优化巴旦木壳对废水Pb、Cu和Cd的吸附及同时测定

研究废弃巴旦木壳对模拟废水中Pb、Cu和Cd的去除率。在单因素试验的基础上,采用响应面法对吸附剂投加量、吸附时间和pH值3因素进行优化。实验结果表明,最佳吸附条件为Pb：为吸附剂投加量0.4g、吸附时间49.38min、pH值为9.96;Cu：吸附剂投加量0.4g、吸附时间49.91min、pH值为10.13;Cd：吸附剂投加量0.4g、吸附时间49.83min、pH值为10.42;在此条件下,Pb、Cu和Cd的去除率分别为87.42%、73.49%和85.11%。采用偏最小二乘法(PLS)对Pb、Cu和Cd模拟混合试样吸附后的溶液进行同时测定,计算得出吸附剂对Pb、Cu和Cd的去除率分别为83.2%、66.0%和83.3%。     

Dilute sulfuric acid pretreatment of agricultural and agro-industrial residues for ethanol production

The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122 degrees C during 20, 40, or 60 min using 2% H(2)SO(4) at a solid-to-liquid ratio of 1:10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7- to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.     

Adsorption of Hydrocarbon Vapors on Activated Carbons Obtained from Vegetable Raw Materials

The equilibrium adsorption of vapors of benzene, toluene, o-xylene, and gasoline in the temperature range 25-100°C and adsorbate content of 0.01-1.80 vol % on activated carbons obtained from plum stones and shells of peanut, walnut, and coconut was studied. The effect of temperature on the adsorption properties of the absorbents were analyzed. The isosteric heats of adsorption were calculated.     

Cellulosic biomass biocomposites with polyaniline,polypyrrole and sodium alginate: Insecticide adsorption-desorption,equilibrium and kinetics studies

This work was designed to synthesize and characterize biocomposites for the adsorptive elimination of insecticide (nitenpyram). Different biocomposites were synthesized of polyaniline (PAN-PH), polypyrrole (PPY-PH) and sodium alginate (Na-Al-PH) with cellulosic biomass of peanut husk (PH), which was characterized fourier-transform infrared spectroscopy (FTIR), pH_pzc and scanning electron microscope (SEM). In batch mode, different variables, i.e., contact time, pH, temperature, NP (nitenpyram) concentration and adsorbent dose effects were investigated. The adsorption capacities of PH, PAN-PH, PPY-PH and Na-Al-PH were recorded to be 13.0, 14.43, 13.61 and 11.91 (mg/g), respectively at 30 °C, 60 min contact time, 0.05 g and 2.0 pH. Pseudo second order kinetic and Freundlich isotherm models best explained the NP adsorption data. An exothermic adsorption nature of NP adsorption was observed on to PH, PAN-PH, PPY-PH and Na-Al-PH. The NP desorption was efficient with NaOH and biocomposites are competent for the adsorptive removal of NP, which can utilized for NP remediation in effluents.