壳聚糖改性蒙脱石对蔗糖溶液中酚酸的吸附性能研究

通过共沉淀法制备壳聚糖改性蒙脱石并用于蔗糖溶液中酚酸的吸附。通过SEM、FT-IR、XPS和BET对其进行表征,由表征结果可知:改性过程成功地将壳聚糖负载到蒙脱石表面,制备出壳聚糖改性蒙脱石;改性蒙脱石等电点为7.84,主要通过静电力和胺基吸附蔗糖溶液中的没食子酸。吸附试验结果表明改性后的蒙脱石对没食子酸吸附性能提高,壳聚糖改性蒙脱石对蔗糖溶液中没食子酸吸附的最佳pH为7.0,平衡时间为600 min。壳聚糖改性蒙脱石对没食子酸的吸附过程更加符合Freundlich模型和准二级吸附动力学方程,吸附过程主要为多分子层吸附和化学吸附,饱和吸附量达到58.82 mg/g。壳聚糖改性蒙脱石具有良好的再生性能,且对蔗糖溶液中酚酸吸附效果良好,是一种有前景的糖用澄清剂。     

锆改性沸石对蔗糖溶液中没食子酸的吸附性能研究

为降低制糖过程中蔗汁中没食子酸的含量,降低白砂糖的色值,以氧氯化锆和沸石为原料,通过共沉淀法制备锆改性沸石,研究改性前后沸石表面结构和基团的变化,考察时间、pH值、温度及没食子酸初始浓度等因素对改性沸石吸附蔗糖溶液中没食子酸的吸附效果的影响,并对吸附动力学模型、吸附等温模型和吸附热力学进行初步探讨。扫描电镜结果显示锆改性后沸石表面更加粗糙,红外光谱显示改性后沸石基团发生了改变,氧化锆成功的负载到改性沸石上。吸附试验结果表明锆改性沸石对没食子酸吸附量达到34.442 mg/g。改性沸石对蔗糖溶液中没食子酸吸附的最佳pH值为8.0,时间为600 min,吸附温度及没食子酸初始浓度的提高有利于提高吸附效果;吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型;通过热力学研究可知吸附过程为吸热过程,能自发进行。     

磁性载锆高岭土对蔗糖溶液中咖啡酸的吸附性能研究

通过共沉淀法制备磁性载锆高岭土,并用于蔗糖溶液中咖啡酸的去除。通过傅里叶红外光谱（Fourier infrared spectroscopy,FTIR）、振动样品磁强计（vibrating sample magnetometer,VSM）和扫描电子显微镜（scanning electron microscope,SEM）表征高岭土改性前后结构和基团的变化,研究其对咖啡酸的吸附特性。结果表明改性后氧化锆和Fe3O4成功地负载到了高岭土上并提升了其对咖啡酸的吸附性能,磁性载锆高岭土的等电点为3.49,酸性条件有利于咖啡酸的去除,吸附在180 min达到吸附平衡。磁性载锆高岭土对咖啡酸的吸附过程更符合准二级动力学和Langmuir等温线吸附模型,吸附过程主要为化学吸附和单分子层吸附,热力学研究表明吸附过程为自发吸热过程。再生性能实验说明磁性载锆高岭土再生次数应该控制在3次以内。     

壳聚糖改性对蒙脱石吸附茶饮料中咖啡碱的影响

通过将壳聚糖负载到蒙脱石表面，制备壳聚糖改性蒙脱石，并利用扫描电子显微镜(scanning electron microscope, SEM)、X射线衍射仪技术(X-ray diffraction, XRD)进行表征，探究改性蒙脱石在脱咖啡碱茶饮料中的应用。结果表明，壳聚糖并未插入蒙脱石层间，而是通过电荷相互作用吸附在蒙脱石表面，形成复合吸附剂。蒙脱石负载壳聚糖的量越多，对咖啡碱的吸附能力越弱，对茶多酚的吸附能力越强。以m(蒙脱石)∶m(壳聚糖)=1∶0.01最佳，此时咖啡碱脱除率约(86.01±1.8)%,茶多酚保留率为(84.52±1.01)%。此外，相较于蒙脱石，负载壳聚糖的蒙脱石能明显抑制铁离子溶出。感官评定显示，壳聚糖改性蒙脱石处理的茶饮料色泽的亮度、香气以及整体滋味更佳。     

硅烷偶联剂改性纳米蒙脱石协同正十二烷乳化ASA

ASA(烯基琥珀酸酐)是在造纸过程中赋予纸和纸板抗渗透性的一种浆内施胶剂。本文研究了硅烷偶联剂改性纳米蒙脱石协同正十二烷乳化ASA,及其乳液稳定性和施胶性能,对改性纳米蒙脱石(MMT)利用X射线衍射(XRD)、傅里叶红外FT-IR、表面接触角等方法进行分析表征。结果表明,KH570成功改性纳米蒙脱石颗粒,并与蒙脱石表面羟基反应而改变颗粒亲水性;当油水比Φ为0.4时,改性蒙脱石用量为2%时,由KH570改性蒙脱石固体颗粒与正十二烷协同乳化稳定的Pickering乳液型ASA乳液稳定性最好;硫酸铝用量为0.6%时,随ASA用量的增加,纸页施胶效果明显提高。     

壳聚糖改性沸石对蔗糖溶液中酚酸的吸附性能研究

为了降低制糖过程中蔗汁中酚类化合物的含量,本研究以壳聚糖和沸石为原料,通过共沉淀法制备壳聚糖改性沸石,研究改性前后沸石表面结构和基团的变化,考察时间、p H及酚酸初始浓度等因素对改性沸石吸附蔗糖溶液中酚酸吸附效果的影响,并对吸附动力学模型和吸附等温模型进行初步探讨。扫描电镜结果显示壳聚糖改性后沸石表面更加粗糙,红外光谱显示改性后复合材料基团发生了改变,壳聚糖成功地负载到了沸石上。吸附试验结果表明壳聚糖改性可以提高沸石对酚酸的吸附能力,改性沸石对酚酸吸附的最佳p H值为8.0,吸附时间为600 min,此时酚酸吸附量达到了33.41 mg/g;酚酸初始浓度的提高有利于提高吸附效果;吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型。壳聚糖改性沸石对蔗糖溶液中酚酸吸附效果良好,是一种有前景的糖用澄清剂。     

球形木质素负载纳米零价铁去除溴酸盐的研究

以球形氰乙基木质素为原料通过液相还原法制备球形木质素负载纳米零价铁材料（LSAC-Fe）,用于去除饮用水中微量的溴酸盐。采用场发射扫描电子显微镜（FESEM）、X射线衍射仪（XRD）、X射线光电子能谱仪（XPS）、氮气吸附法（BET）等对其结构进行表征,并探究了不同条件下LSAC-Fe对BrO-3的吸附效果及其热力学吸附和去除机理。研究表明,纳米零价铁可较为均匀地负载在球形木质素上,并且LSAC-Fe具有很高的表面活性;BrO-3的去除率随着初始溶液pH值的升高而降低,随着BrO-3初始溶液质量浓度的增加而降低;LSAC-Fe对BrO-3的吸附过程为吸热过程,升温可促进LSAC-Fe对BrO-3的吸附。     

改性生物炭对考马斯亮蓝的吸附研究

以废弃小麦桔杆为原料制备了生物炭,经KOH改性后,用于印染废水中考马斯亮蓝(CBG)的吸附。采用X射线粉末衍射(XRD)、比表面积分析和拉曼光谱对其结构进行了表征。采用静态吸附实验,研究了吸附剂用量、染料初始质量浓度、溶液pH等因素对改性生物炭吸附考马斯亮蓝的影响。结果表明:生物炭经KOH改性后比表面积明显增大,吸附性能明显提高。     

蒙脱石及改性蒙脱石对赖氨酸、蛋氨酸及VB2的吸附作用

研究了蒙脱石及改性蒙脱石对赖氨酸、蛋氨酸、VB2的吸附规律。研究结果表明，在pH2．0和pH8．0时，蒙脱石对赖氨酸的最大吸附量分别为64．1和49．26mg/g，改性蒙脱石对赖氨酸的最大吸附量分别为45．45和33．78mg／g。在蛋氨酸含量低于0．2％时，蒙脱石和改性蒙脱石对蛋氨酸不吸附。蒙脱石及改性蒙脱石对VB2的吸附符合Nemst模型，为分配吸附。蒙脱石及改性蒙脱石吸附赖氨酸及VB2后，可被部分解吸。改性蒙脱石对赖氨酸、VB2的吸附量较蒙脱石低，而解吸率较蒙脱石高，提示蒙脱石经改性处理后．可以获得更好的应用价值。     

磁性活性炭的制备及其对亚甲基蓝的吸附性能

以玉米淀粉为原料,采用两步水热法制备磁性活性炭,并用X射线衍射仪、扫描电镜、透射电镜、比表面仪和X射线光电子能谱仪进行表征。以亚甲基蓝溶液模拟印染废水,研究活化剂ZnCl_2用量、FeCl_3用量、磁性活性炭用量和吸附时间对印染废水处理效果的影响。结果表明:磁性活性炭为介孔结构,比表面积为120.2 m~2/g;Fe_3O_4纳米颗粒成功附着在活性炭表面;考虑成本和能耗问题,在ZnCl_2用量10 g、FeCl_3用量3 g、磁性活性炭用量100 mg、吸附时间90 min的条件下,催化剂对亚甲基蓝溶液的处理效果最佳,去除率达到93.4%。     

Phosphate adsorption on aluminum-impregnated mesoporous silicates: surface structure and behavior of adsorbents

Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface structure of the materials was investigated with X-ray diffraction (XRD), a N2 adsorption-desorption technique, Fourier transform-infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) to understand the effect of surface properties on the adsorption behavior of phosphate. The mesoporous materials were loaded with Al components by reaction with surface silanol groups. In the adsorption test, the Al-impregnated mesoporous materials showed fast adsorption kinetics as well as high adsorption capacities, compared with activated alumina. The uniform mesopores of the Al-impregnated mesoporous materials caused the diffusion rate in the adsorption process to increase, which in turn caused the fast adsorption kinetics. High phosphate adsorption capacities of the Al-impregnated mesoporous materials were attributed to not only the increase of surface hydroxyl density on Al oxide due to well-dispersed impregnation of Al components but also the decrease in stoichiometry of surface hydroxyl ions to phosphate by the formation of monodentate surface complexes.     

磺化还原氧化石墨烯的制备及其对碱性染料的吸附研究

本研究探索了磺化还原氧化石墨烯的制备及其对碱性染料的吸附性能。通过接枝含有芳香自由基的磺酸根到还原氧化石墨烯(rGO)来制备磺化还原氧化石墨烯(S-rGO)纳米片材。通过红外光谱、X射线光电子能谱和扫描电镜对合成的吸附剂磺化还原氧化石墨烯(S-rGO)进行了表征,结果表明磺酸根被成功地接枝到氧化石墨烯上。本研究系统地研究了p H、时间和吸附剂量等对吸附行为的影响。吸附实验结果表明,吸附过程遵从准二级动力学模型和Langmuir模型,表明该吸附由表面反应过程所控制,属于单分子层吸附。吸附解吸实验中碱性橙21、硫黄素T和罗丹明B的吸附率均大于99%,解析率分别达到98.81%、86.63%和94.44%,表明吸附剂S-r GO对碱性染料有很好的吸附解吸性能且可重复使用。使用该材料处理工业废水可防止有害染料污染农产品后在食物链中地不断富集,从而危害人类健康。     

膨润土的有机改性及吸附性能研究

以十六烷基三甲基溴化铵(HTMAB)、自制的低分子质量聚胺及四甲基铵对膨润土进行有机改性,通过红外光谱、X射线检测分析证实,HTMAB可有效地与膨润土进行复合,并以一定角度倾斜于层间。不同有机胺改性膨润土对松香酸吸附性能的研究结果表明,改性膨润土中需复合一定强度的有机相,才能更有效地吸附有机污染物松香酸。     

Functionally Modified Cellulose Nanocrystals as an Adsorbent for Anionic Dyes

Cellulose nanocrystal was modified with poly(N,N-diethy-laminomethyl methacrylate) to prepare an adsorbent containing amine groups for removing anionic dyes from waste water. The prepared adsorbent was characterized by Fourier-transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The adsorption was affected by various factors, such as the contact time, adsorbent dosage, dye solution pH value, initial dye concentration, and ionic strength. The results revealed that amine functional groups mainly contribute to the adsorption of azo dyes (AO7). The adsorbent showed pseudo-second-order adsorption kinetics, indicating that the dye molecules were chemisorbed on the adsorbent. The adsorption isotherm was found to fit better with the Langmuir isotherm model than with the Freundlich isotherm model.     

Characterization and reactivity of MnO(x) supported on mesoporous zirconia for herbicide 2,4-D mineralization with ozone

Manganese oxide was supported on mesoporous zirconia (MnO(x)/ MZIW) by wet impregnation, drying, water washing, and calcinations with manganese acetate tetrahydrate as the metal precursor for the first time and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectra (FTIR), temperature-programmed reduction (TPR), temperature-programmed oxygen desorption (O2-TPD), and UV-vis diffuse reflectance spectra (UV-vis DRS) measurements. The catalyst was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) aqueous solution with ozone. The characterization studies showed that nonstoichiometrically MnO(x) was highly dispersed on mesoporous zirconia by the strong interaction of the [Mn(H2O)6]2+ complex with surface hydroxyls of the support. Moreover, the multivalence oxidation states of MnO(x) enhanced the electron transfer, causing the higher catalytic reactivity. On the basis of all information obtained under different experimental conditions, MnO(x)/MZIW enhanced the mineralization of 2,4-D by the formation of *OH radicals resulting from the catalytic decomposition of ozone.     

Arsenate adsorption on an Fe-Ce bimetal oxide adsorbent: role of surface properties

An Fe-Ce bimetal adsorbent was investigated with X-ray powder diffraction (XRD), transmission electron micrograph (TEM), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS) methods for a better understanding of the effect of surface properties on arsenate (As(V)) adsorption. In the adsorption test, the bimetal oxide adsorbent showed a significantly higher As(V) adsorption capacity than the referenced Ce and Fe oxides (CeO2 and Fe3O4) prepared by the same procedure and some other arsenate adsorbents reported recently. XRD measurement of the adsorbent demonstrated that the phase of magnetite (Fe3O4) disappears gradually with the increasing dosage of Ce4+ ions until reaching a molar ratio of Ce4+ to Fe3+ and Fe2+ of 0.08:0.2:0.1 (Fe-CeO8 refers to the adsorbent prepared at this ratio), and the phase of CeO2 begins to appear following a further increase of the Ce dose. Combined with the results of TEM observation, it was assumed that a solid solution of Fe-Ce is formed following the disappearance of the magnetite phase. Occurrence of a characteristic surface hydroxyl group (MOH, metal surface hydroxyl, 1126 cm(-1)), which showed the highest band intensity in the solid solution state, was confirmed on the bimetal oxide adsorbent by FTIR. Quantificational calculation from the XPS narrow scan results of O(1s) spectra also indicated that the formation of the bimetal Fe-CeO8 was composed of more hydroxyl (30.8%) than was the formation of CeO2 and Fe3O4 (12.6% and 19.6%). The results of adsorption tests on Fe-CeO8 at differentAs(V) concentrations indicated that both the integral area of the As-O band at 836 cm(-1) and the As(V) adsorption capacity increased almost linearly with the decrease of the integral area of M-OH bands at 1126 cm(-1), proving that the adsorption of As(V) by Fe-CeO8 is mainly realized through the mechanism of quantitative ligand exchange. The atomic ratio of Fe on Fe-CeOB decreased from 20.1% to 7.7% with the increase of the As atom ratio from 0 to 16% after As(V) adsorption, suggesting that As(V) adsorption might be realized through the replacement of the M-OH group of Fe (Fe-OH) with arsenate. The well splitting of three v3 bands at As-O band (836 cm(-1)) of FTIR and the hydroxyl ratio (1.7) of Fe-CeO8 calculated from the XPS results suggested that the diprotonated monodentate complex (SOAsO(OH)2) is possibly dominant on the surface of Fe-CeO8.     

金属-有机骨架负载磷钼酸处理漂白废水中AOX的研究

利用锆系金属有机骨架(UiO-66)负载磷钼酸(PMA)制备负载型催化剂(PMA@UiO-66),通过傅里叶变换红外光谱仪(FT-IR)、X射线衍射仪(XRD)、比表面积和孔径分析仪(BET)、扫描电子显微镜(SEM)、热重分析仪(TG)、X射线光电子能谱仪(XPS)等手段对其结构进行了表征;分析了在H2O2的氧化作用下,负载型催化剂PMA@UiO-66对制浆漂白废水中可吸附有机卤化物(AOX)的去除效果,并研究了PMA@UiO-66的回用及其稳定性。结果表明,PMA成功负载在金属骨架上,且不会影响金属骨架UiO-66的晶体结构,PMA@UiO-66具有大的比表面积和孔径,有利于污染物进入活性位点;在PMA@UiO-66/H2O2的作用下,漂白废水中AOX和总有机碳(TOC)的去除率分别可达55.7%和60.0%;PMA@UiO-66具有良好的回用性和稳定性,循环4次之后AOX的去除率为51.8%且反应前后PMA@UiO-66的结构未发生变化。     

磁性壳聚糖改性对高岭土吸附蔗糖溶液中咖啡酸性能的影响

目的:研究磁性壳聚糖改性高岭土对模拟蔗汁中咖啡酸的吸附特性。方法:通过共沉淀法将壳聚糖、纳米四氧化三铁与高岭土结合制备成磁性壳聚糖改性高岭土,通过FT-IR、VSM和SEM表征高岭土改性前后表面结构和基团变化,采用吸附试验研究磁性壳聚糖改性高岭土对咖啡酸的吸附特性。结果:改性后壳聚糖和纳米Fe₃O₄成功地负载到了高岭土上并提升了其对咖啡酸的吸附性能,磁性壳聚糖改性高岭土的等电点为4.54,酸性条件有利于咖啡酸的去除,并在240 min时达到吸附平衡。磁性壳聚糖改性高岭土对咖啡酸的吸附过程更符合准二级动力学和Langmuir等温线吸附模型,其吸附过程主要为化学吸附和单分子层吸附,热力学研究表明吸附过程为自发吸热过程。结论:磁性壳聚糖改性高岭土对蔗汁中咖啡酸具有较强吸附性能,可作为糖用澄清剂用于蔗汁中咖啡酸的吸附处理。