蔗渣酶法水解过程的膜分离研究

以直接加热膨胀蔗渣为酶解底物，采用日本Ｙａｋｕｌｔ公司生产的纤维素酶（Ｏｎｏｚｕｋ ＲＳ）进行酶法水解反应，同时开展膜分离实验研究，为该系统优选了膜材料和膜规格，测定了膜分离的有关特性并进行了膜洗涤尝试。实验表明：分割分子量为１．０万的聚醚砜膜对纤维素酶的截留率为１００％；发酵液与膜的吸附对通量的影响不明显，即在发酵液中浸泡过的膜的初始通量与未浸泡过的没多大差别；本实验条件下酶的回收率（以总活性计     

Enhanced Adsorption of Malachite Green by EDTAD-modified Sugarcane Bagasse

Abstract

Ethylenediaminetetraacetic dianhydride (EDTAD) modified sugarcane bagasse (SB) was prepared and characterized by Fourier transform infrared spectroscopy (FTIR). Due to the presence of a large number of carboxyl groups, the adsorption capacity of the EDTAD modified SB (EDTAD-SB) for malachite green (MG) showed a significant increase compared with SB. Increase in ion strength of solution-induced decline of MG sorption. The maximum adsorption capacities were 157.2 mg g^?1 for MG, according to the Langmuir equation. Kinetic studies showed better correlation coefficients for a pseudo-second-order kinetic model, confirming that the sorption rate was controlled by a chemisorption process.     

基于甘蔗渣生物吸附重金属污染物的研究

用甘蔗渣作为生物吸附质,研究了甘蔗渣对水中铅铜离子吸附能力及影响因素,探讨了吸附质粒径、pH值、吸附时间和投加量等因素对铅离子和铜离子吸附的影响。结果表明:甘蔗渣吸附两种重金属的适宜粒径应大于140目,适宜pH为4~6,超过7则因氢氧化物沉淀生成而影响吸附;甘蔗渣对两种重金属的吸附很快,1.5 h就近乎达到衡;甘蔗渣对铅的吸附性能要优于铜,对铅最大吸附量可以达到41.32 mg/g,去除率为91.83%,对铜的最大吸附量可达到30.62 mg/g,去除率为68.05%;同时甘蔗渣对铅和铜的竞争吸附实验表明,铅和铜对甘蔗渣上基团的吸附存在竞争使得吸附量相对于正常条件下有较大的降低。     

蔗渣纤维素乙醇的预处理技术研究进展

从蔗渣的物化特性及预处理的必要性出发,综述了近年来国内外预处理蔗渣方面发展的不同技术途径(包括物理法、化学法、生物法和联合法)及其研究进展,对各种技术的作用效果和特点进行了总结和对比分析,并对蔗渣预处理技术的发展方向予以展望。蔗渣作为糖厂的主要副产物,具有量大、集中且纤维含量高等特点,是生产第二代生物乙醇的重要潜在原料之一,对其进行有效预处理是利用其制取生物乙醇的关键,直接影响着后续的酶解糖化和乙醇发酵效果。     

Adsorption Performances of Cationic Dyes from Aqueous Solution on Pyromellitic Dianhydride Modified Sugarcane Bagasse

In this study, pyromellitic dianhydride (PMDA) modified waste sugarcane bagasse (SCB) was prepared through a simple method to remove two cationic dyes: methylene blue (MB) and malachite green (MG) from aqueous solution. Adsorption performances of MB and MG on the modified sorbent were investigated in details. The adsorption capacities of the modified SCB for MB and MG were 571.4 and 377.4 mg g^?1, respectively, which were 10 and 12 times than that obtained on the unmodified SCB. Adsorption kinetics study showed equilibriums were obtained after adsorption for 13 hours for both dyes. The modified SCB could be used repeatedly after regeneration. FTIR results showed that carboxyl and hydroxyl groups on the modified SCB involved in adsorption process.     

银耳对水中重金属的吸附性能的研究

结合当前重金属污染的水质处理技术的处理方法,本课题选用银耳作为吸附剂研究了其对水中微量重金属Cu、Pb、Zn、Cd、Cr(六价)(以下简称Cr)的吸附性能,分别考察了原液浓度、吸附剂用量、pH、温度对吸附的影响,研究了吸附发生的最佳条件,并通过动力学吸附模型和平衡吸附模型对吸附结果做了分析研究。     

氢氧化钠预处理对甘蔗渣酶解和发酵性能的影响

采用氢氧化钠预处理甘蔗渣,通过单因素和正交试验考察了不同预处理条件对甘蔗渣酶解和发酵性能的影响,并进一步分析了比表面积和木质素含量对酶解性能的影响。结果表明：预处理温度、氢氧化钠质量分数及预处理时间对酶解和发酵效率影响较为显著,最佳的预处理条件为：温度85℃、时间11 h、NaOH质量分数4.5%,在此优化条件下预处理的甘蔗渣,含纤维素56.46%,与原料相比提高了46.16%;半纤维素20.30%、Klason木质素5.79%,与原料相比分别降低了15.77%和72.87%,酶解36 h的还原糖得率为0.69 g/g（以甘蔗渣质量计）。经过氢氧化钠预处理后的甘蔗渣比表面积显著增加（由原料的0.07 m²/g最大可增加到1.07 m²/g）,木质素显著降低,有利于提高酶解和发酵效率。当比表面积超过0.30 m²/g时,酶解初始速率和酶解效率达到平衡;当木质素低于11%时,酶解效率达到平衡。     

木质素及其衍生物对重金属离子吸附性能研究进展

木质素是一种有机高分子,大量存在于木材、竹材、秸秆、草类及其它植物材料中。但由于其结构复杂,导致应用受到很大的限制。有效利用好木质素这种可再生资源已成为科研工作者研究的出发点。木质素吸附剂是近年来木质素高值化利用研究的热点。文章在简要介绍木质素的化学结构及其分子修饰基础上,对木质素及其衍生物近年来在重金属离子的吸附研究进行了综述。     

蔗渣闪爆处理及其黄原酸化物的制备和应用

采用热蒸汽适度闪爆及稀碱洗涤等预处理技术对蔗渣进行纯化和活化,利用处理后的蔗渣纤维素合成纤维素基黄原酸酯,对其在水处理中的应用进行了研究。研究优化了闪爆处理的工艺条件,并采用IR、SEM和化学分析技术对闪爆前后蔗渣纤维的形态、结构、a-纤维素的含量进行了分析,对处理前后的蔗渣纤维的碱化和黄原酸化合成条件进行了优化。结果表明,闪爆预处理技术是一种便宜、迅速、无污染的技术,蔗渣纤维素基黄原酸酯对含金属离子的污水有良好的处理效果。     

Synthesis of Amine-Functionalized MCM-41 and MCM-48 for Removal of Heavy Metal Ions from Aqueous Solutions

In this research amino functional mesoporous MCM-41 and MCM-48 materials were prepared in an attempt to develop efficient adsorbents for removal of heavy metals from aqueous solutions. The adsorbents were characterized by XRD, FTIR, and TG-DTG techniques. The synthesized adsorbents were used for the removal of Cu(II), Co(II), Cd(II), and Pb(II) from aqueous solutions for the first time, and the influence of some effective parameters including concentration, initial pH, contact time, and temperature on the sorption process was studied and optimized. Significant adsorption capacities were obtained at low concentrations. The kinetic studies showed that the adsorption process was fast and more than 90% of equilibrium capacity was achieved within 60 min. Experimental kinetic data was well fitted with the pseudo-second-order kinetic model. Thermodynamic parameters computed from the experimental data showed that the adsorption was endothermic and spontaneous.     

Systematic Isolation and Utilization of Lignocellulosic Components from Sugarcane Bagasse

Lignocellulosic constituents as renewable feedstock can be utilized for various applications. A systematic procedure for separation of cellulose and lignin followed by hydrolysis of hemicelluloses was proposed in this study. Sugarcane bagasse was first subjected to alkaline hydrolysis to remove lignin and hemicelluloses. Then cellulose was separated from the alkali pretreatment residue and further purified. Meanwhile, the obtained pre-hydrolysis liquor (PHL) was acidified to precipitate lignin, and the filtrate was hydrolyzed with 1-methylimidazolium hydrogen sulfate ([Hmim]HSO₄) to prepare furfural. Response surface methodology (RSM) was employed to determine optimal conditions for isolation of cellulose. The sequential treatments resulted in a total release of over 77.3% of the original cellulose and 84.5% of the original lignin. In particular, 7.5% yield of furfural was obtained. The structures of the isolated cellulose and lignin were elucidated with Fourier transform infrared spectroscopy (FT-IR).     

重金属在土壤上的竞争吸附研究进展

对重金属离子在土壤上的竞争吸附行为进行了综述。讨论了影响重金属离子竞争吸附的一些主要因子（pH和离子强度）、等温吸附模型及吸附动力学模型。并对竞争吸附研究做出了展望。     

底泥吸附及释放重金属的研究

水体受重金属污染后其底泥亦成为污染面源。本文结合底泥中重金属的分析方法介绍了其赋存形态。分析讨论了pH值、温度、粒径、盐度、腐殖酸、氧化还原电位、泥水比等因素对底泥吸附及释放重金属的影响,总结了底泥吸附重金属的热力学及动力学、底泥释放重金属的动力学等相关规律．并对底泥中重金属的释放研究及其污染防治工作做出了展望。     

过氧化氢-乙酸联合预处理对甘蔗渣酶解和发酵的影响

采用过氧化氢-乙酸(HPAC)对甘蔗渣(SCB)进行了联合预处理。以预处理后的甘蔗渣为原料,先进行酶水解,然后将水解液进行乙醇发酵,探讨预处理对甘蔗渣酶解和发酵的影响。实验结果表明：20 g甘蔗渣,加入150 mL过氧化氢水溶液(75 mL过氧化氢(30%)和75 mL水)和150 mL乙酸(99%),硫酸用量为过氧化氢-乙酸溶液体积的0.5%,在70℃反应2 h时,HPAC预处理脱除了88.85%的木质素,并使90.10%的纤维素保留在底物中。底物(HPAC/70-SCB-0.5)的酶可及度是80.30 mg/g,与相同条件下单独过氧化氢预处理(HP/70-SCB)和单独乙酸预处理(AC/70-SCB)相比,分别增加了38.26%和31.08%,甘蔗渣木质素的表面覆盖率从原料的0.66降低至0.22。酶解上清液在酶用量为5 FPIU/g(以底物计)条件下水解后,葡萄糖得率是87.63%,分别是HP/70-SCB和AC/70-SCB的6.89和20.62倍,发酵产乙醇质量浓度是7.57 g/L,分别是HP/70-SCB和AC/70-SCB的7.65和22.94倍。     

过氧甲酸预处理对甘蔗渣酶解和发酵的影响

以甘蔗渣(SCB)为原料,经过氧甲酸(PAP)预处理后加入酶进行水解,并以水解液发酵产乙醇,考察预处理时过氧化氢(HPP)浓度变化对甘蔗渣酶解和乙醇得率的影响。实验结果表明：在甘蔗渣PAP预处理过程中,HPP与甲酸(FAP)体积比为1∶1时,预处理甘蔗渣(PAP-SCB-1)的木质素脱除率达84.30%;在纤维素酶用量为10 FPIU/g(以预处理后的甘蔗渣质量计)时,PAP-SCB-1水解72 h葡萄糖得率为98.71%,较单独过氧化氢预处理甘蔗渣(HPP-SCB,葡萄糖得率9.11%)和单独甲酸预处理甘蔗渣(FAP-SCB,葡萄糖得率7.06%),分别提高了9.84和12.98倍;PAP-SCB-1水解液经24 h发酵后,乙醇得率为84.06%,比HPP-SCB(76.20%)和FAP-SCB(75.15%)均有增加。对预处理前后物料的化学成分变化、比表面积和结晶度进行测定,结果显示：经PAP预处理后可以显著脱除甘蔗渣中的木质素,木质素的量由未经预处理的21.27%降低到10%以下;比表面积和结晶度都有提高,PAP-SCB-1的比表面积和结晶度分别为13.01 m²     

蔗渣纤维素黄原酸酯的制备及应用研究

蔗渣纤维素经碱化后,与二硫化碳反应,得蔗渣纤维素黄原酸酯(CX).以产物的应用效果为目标,用正交设计法研究了蔗渣纤维素黄原酸酯合成的最佳工艺条件,并探讨了它对重金属离子的交换性能.实验结果表明,CX处理含重金属离子的溶液可达到国家排放标准,是一种效率较高且价廉的污水处理剂.     

Adsorption of Heavy Metals from Aqueous Solutions onto Activated Carbon in Single Cu and Ni Systems and in Binary Cu–Ni,Cu–Cd and Cu–Zn Systems

Single copper and nickel adsorption from aqueous solutions onto a granular activated carbon is reported. Metal removals increase on raising pH and temperature, and decrease on raising the initial metal concentration at constant carbon dose. The adsorption processes are modelled using the surface complex formation (SCF) Triple Layer Model (TLM) with an overall surface bidentate species. A dependence of the SCF constant on pH, initial molar metal/carbon ratio and temperature is observed, and a correlation for log K_ads is determined. The SCF model successfully predicts copper and nickel removals in single metal solutions. Adsorption in the binary metal systems copper–nickel, copper–cadmium and copper–zinc is also reported, showing competitive adsorption effects. © 1997 SCI.     

Batch Removal of Crystal Violet from Aqueous Solution by H2SO4 Modified Sugarcane Bagasse: Equilibrium,Kinetic, and Thermodynamic Profile

Batch adsorption studies were carried out using H₂SO₄ modified sugarcane bagasse (HMSB) for the removal of hazardous Crystal Violet (CV) dye from aqueous solutions. The effects of initial solution pH, adsorbent dose, and temperature on the adsorption process were investigated. The Langmuir isotherm model well described the equilibrium dye uptake while the pseudo-second-order kinetic model showed good agreement with the experimental kinetic data. Gibb's free energy change (ΔG⁰) was spontaneous for all interactions, and the adsorption process exhibited endothermic enthalpy values. Results suggest that HMSB is an effective adsorbent for the removal of CV from wastewater.