改性柏树锯末对铜离子吸附机制研究

本文以KMnO₄改性处理的柏树锯末为吸附剂,对溶液中的Cu²⁺吸附去除。结果表明,改性锯末增大了孔径和比表面积,吸附剂表明吸附位点增多,当pH=7、吸附剂用量1 g·L^-1及温度318 K的条件下吸附效果最佳。改性柏树锯末对Cu²⁺的吸附动力学和等温线线性拟合结果分别符合准二级动力学方程和Langmuir吸附等温模型,说明该吸附过程是单分子层吸附,并以化学吸附为主。     

Study on the adsorption of heavy metals by a new magnetic hydrogel based on acrylic acid/ acrylamide/ sodium p-styrenesulfonateEI北大核心CSCD

通过水溶液法将Fe₃O₄@SiO₂负载到丙烯酸（AA）-丙烯酰胺（AM）-对苯乙烯磺酸钠（SSS）三元共聚水凝胶上,制备了具有高吸附能力的磁性水凝胶P（AA/AM/SSS）/Fe₃O₄@SiO₂。通过傅里叶变换红外光谱,X射线衍射光谱,拉曼光谱和比表面孔径分析表征了磁性水凝胶的微观结构。该磁性水凝胶平均孔径3.1 nm,属于介孔材料,且具有较好的热稳定性。吸附性能研究发现其对重金属离子Pb²⁺,Cu²⁺,Co²⁺,Cd²⁺和Ni²⁺均显示出较高的去除率,其中对Pb²⁺表现出优异的选择性,最大吸附量为497 mg/g。吸附动力学研究表明,吸附过程遵循拟二级动力学模型。再生实验发现该水凝胶经过7次吸附-解吸循环后,磁性水凝胶饱和吸附容量仍保持在265 mg/g。     

没食子酸修饰的超高交联吸附树脂对2,4-二氯苯氧乙酸的吸附性能研究

通过后交联反应和化学修饰反应制备了没食子酸修饰的超高交联吸附树脂(GAMR),以大孔吸附树脂XAD-4树脂为对照,研究了GAMR对水中2,4-二氯苯氧乙酸(2,4-D)的吸附性能.实验结果表明:GAMR具有较丰富的微孔,比表面积和微孔面积分别为1 232.3和899.5 m²·g^-1.GAMR对2,4-D的吸附动力学过程符合准一级动力学方程,吸附过程同时存在物理吸附和化学吸附.Freundlich等温方程能较好地拟合GAMR对2,4-D的吸附等温线.GAMR对2,4-D吸附过程的ΔG为负值,ΔH和ΔS均大于0,表明吸附是自发、吸热和熵增加的过程.与XAD-4相比,所制备的GAMR对2,4-D的吸附去除率显著提高.     

Ni-MOFs@GO复合材料吸附亚甲基蓝工艺优化及其性能研究

为了提高氧化石墨烯(GO)对阳离子染料的吸附效果,采用溶液共混法制备Ni-MOFs@GO复合材料。采用X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)和扫描电子显微镜(SEM)对其结构和形貌进行了表征。采用响应曲面法(RSM)优化Ni-MOFs@GO对亚甲基蓝(MB)的吸附工艺。以Ni-MOFs@GO浓度、MB质量浓度和吸附温度3因素为变量,以MB吸附量为响应值,建立了二项式回归模型方程,确定最佳吸附条件,并进行动力学和热力学分析。结果表明：3因素的一次项和二次项对MB的吸附效果影响显著,交互项影响不明显。Ni-MOFs@GO对MB最佳吸附条件为Ni-MOFs@GO浓度为0.6 g·L^-1,MB质量浓度为30 mg·L^-1,吸附温度为26℃,MB吸附量为259.83 mg/g;吸附过程符合准二级动力学方程,吸附模型符合Freundlich等温线方程。     

油页岩飞灰对重金属离子的吸附动力学及热力学

采用批式振荡吸附法研究了燃油页岩电厂循环流化床锅炉飞灰对重金属离子Pb²+、Cu²+、Zn²+、Cd²+的吸附动力学及吸附热力学特性,并提出了吸附机理。结果表明,油页岩飞灰对Pb²+、Cu²+、Zn²+、Cd²+的吸附平衡数据符合Langmuir和Freundlich吸附等温方程,但Freundlich方程能够更好地描述吸附等温线。在油页岩飞灰对重金属离子吸附的初始阶段,拉格朗日准一级动力学方程、准二级动力学方程、Elovich方程、粒子内扩散模型均能很好地反映吸附模式,而整个吸附过程则遵循二级反应动力学方程,其吸附过程是液膜扩散和粒子内扩散共同作用的结果。油页岩飞灰对Pb²+、Cu²+、Zn²+、Cd²+的吸附是吸热反应。     

MIL-101(Cr)材料的合成及对水中布洛芬的吸附研究

制备了MIL-101(Cr)材料,借助X-射线衍射和红外光谱技术确认了标题化合物的结构,利用扫描电子镜(SEM)技术及物理吸附技术表征了其形貌特征与孔结构特征。结果表明MIL-101(Cr)材料大小均匀,平均粒径为0.8μm, BET比表面积与总孔容积分别为1505 m²·g^-1和0.11 cm³·g^-1。随后进行了对布洛芬的吸附研究,结果表明MIL-101(Cr)对布洛芬的吸附在30 min即可达到平衡,且为拟一级动力学过程,符合Langmuir吸附模型,最大吸附量为136.3 mg·g^-1。10 mg MIL-101(Cr)吸附剂可实现20 mg·L^-1布洛芬溶液中溶质的98%去除率。以上实验结果可为探究MIL-101(Cr)在水中有机污染物的去除提供参考。     

羧基微孔有机网络材料的合成及其对水中苯并三唑类污染物的快速吸附与去除

以富含羧基的反应单体合成了比表面积大、溶剂和热稳定性好的羧基微孔有机网络材料MON-2COOH,开展了其用于快速吸附和去除水中苯并三唑类污染物的研究。通过固体核磁碳谱、N₂吸附-解吸、傅里叶变换红外光谱、热重分析、扫描电镜和水接触角实验对所合成的MON-2COOH进行了表征。考察了MON-2COOH吸附1H-苯并三唑(BTri)和5-甲苯基三唑(5-TTri)的吸附等温线、吸附动力学和热力学,以及离子强度、p H值和腐殖酸等对吸附的影响。BTri和5-TTri在MON-2COOH上的吸附符合准二级和Langmuir吸附模型。MON-2COOH在10 min内即可实现对BTri和5-TTri(100 mg·L^-1)的吸附平衡,最大吸附量分别为251.3、369.0 mg·g^-1,优于文献报道的大多吸附剂。MON-2COOH还具有良好的可重复使用性和再生性,并成功用于实际水样中BTri和5-TTri的吸附和去除。机理研究表明π-π、疏水和氢键相互作用在吸附过程中起重要作用。该文为设计和合成高效去除苯并三唑类污染物的吸附剂提供...     

Fe@Fe3C-C的制备及对双酚A的高效吸附

该研究制备了铁基金属有机骨架MIL-88B(Fe)衍生磁性多孔碳材料Fe@Fe₃C-C,并将其用于水中双酚A(BPA)的高效吸附。采用X射线衍射、扫描电镜和比表面积及孔径分析等手段对材料的晶体结构、形貌和比表面积进行表征。结果表明,在高温作用下,MIL-88B(Fe)转化成Fe、Fe₃C共掺杂碳材料(Fe@Fe₃C-C)。Fe@Fe₃C-C呈具有层次的炸裂状薄片结构且表面较为粗糙,比表面积为280.48 m²/g,与MIL-88B(Fe)相比增加了17倍。吸附实验表明,与MIL-88B(Fe)相比,高温煅烧(≥600℃)可以明显提升吸附性能。0.5 g/L的Fe@Fe₃C-C在10 min内对10 mg/L的BPA去除率高达95%。材料具有较广的pH值适用范围(pH 2.0～10.0)和较强的抗无机盐离子(100 mmol/L)干扰能力,并能够用于高盐环境下的BPA吸附。拟二级动力学模型符合BPA在Fe@Fe₃C-C上的吸附动力学曲线...     

改性层状双氢氧化物对铜离子(Ⅱ)和双酚A的协同吸附

采用离子交换法制备了十二烷基苯磺酸根(DBS^-)和柠檬酸根(Cit^3-)复合改性层状双氢氧化物(LDHs),简写为DBS-Cit-LDHs。 利用粉末X射线衍射分析、红外光谱分析、比表面积测定以及元素分析等技术手段对样品进行了表征。 结果表明,DBS^-和Cit^3-已柱撑进入LDHs层间。 研究了DBS-Cit-LDHs对水中重金属离子Cu²⁺和有机污染物双酚A(BPA)的协同吸附性能。 吸附实验结果表明,DBS-Cit-LDHs能同时高效去除Cu²⁺和BPA;对Cu²⁺的强吸附能力缘于DBS-Cit-LDHs层间Cit^3-与Cu²⁺形成了稳定配合物;对BPA的强吸附能力缘于分配作用,且吸附能力与样品比表面积无关。 DBS-Cit-LDHs对Cu²⁺的吸附动力学和热力学分别符合准二级动力学方程和Freundlich等温式;对BPA的吸附分别符合准一级动力学方程和Linear等温式。 二者吸附过程的ΔG^o和ΔH^o均为负值,表明吸附为自发放热过程。     

银基负载的氧化石墨烯磁性纳米复合材料的合成、表征及其对2,4-二氯酚的吸附

以溶剂热法制备得到磁性Ag/AgCl@Fe₃O₄@GO纳米复合材料,利用透射电镜(TEM)、扫描电镜(SEM)、X射线能谱(EDX)和N₂吸附-脱附对样品的结构和形貌进行测试表征,研究了材料对水溶液中2,4-二氯酚(2,4-DCP)的吸附性能。此纳米复合材料由具有介孔结构的球形磁性纳米颗粒Ag/AgCl@Fe₃O₄负载在一层带褶皱的氧化石墨烯表面制备而成,平均孔径S_p为13.98 nm,比表面积为46.91 m²/g,孔体积为0.1791 cm³/g。Ag/AgCl@Fe₃O₄@GO复合材料对2,4-DCP的吸附实验表明,对于20 mg/L 2,4-DCP溶液,20 min基本达到吸附平衡,吸附量为13.74 mg/g;吸附以拟二级动力学模型为主导,相关系数为0.9995;吸附符合Langmuir模型,相关系数为0.9841～0.9972,为单分子层吸附;吸附热力学参数...     

Genotoxicity of dimethylarsinous acid: high induction of tetraploids

Arsenic is a carcinogen in humans. However, neither the mechanism of action nor the ultimate chemical form of arsenic which causes cancer has been clearly defined. Dimethylarsinous acid is detected in the urine of individuals who ingest arsenic‐polluted drinking water. The cytogenetic study in V79 cells using iododimethylarsine, which is easily hydrolyzed to dimethylarsinous acid in water, revealed that dimethylarsinous acid was very cytotoxic (50% growth inhibition concentration; 1.1 ± 0.14 µM ), and either induced aneuploids or a high rate of tetraploids (73% at 2.5 µM ). Dimethylarsinous acid caused mitotic arrest, since the mitotic index at toxic dose (5 µM ) was 13.9%, significantly higher than the control (2.7%). Dimethylarsinous acid significantly increased sister chromatid exchange (SCE) and chromosomal aberrations, most of which were chromatid gaps and chromatid breaks. The cytotoxicity and the activity of dimethylarsinous acid in inducing chromosomal aberration or SCE was as effective as arsenite, but the activity was much lower than that of mitomycin C, which was used as a positive control. The most potent effects of dimethylarsinous acid on the cells were induction of aneuploids, tetraploids and c‐mitosis. Our results suggest that toxicity of dimethylarsinous acid is strongly related to the disturbance of the normal cell cycle. Copyright © 2005 John Wiley & Sons, Ltd.     

有序介孔二氧化硅对正丁醛的吸附性能

合成了一系列具有不同孔结构与性质的有序介孔二氧化硅材料SBA-15、MCM-41、SBA-16、KIT-6, 同时通过改变水热温度制备了不同孔径大小的SBA-15, 并利用小角X射线散射、透射电镜、扫描电镜和氮气吸附-脱附等手段, 对其介孔结构进行了表征. 以正丁醛为探针分子, 考察了其对有机醛的吸附, 并与Y-沸石的吸附性能做了对比. 结果表明, 材料的介孔比表面积与其对正丁醛的吸附量成正比, 吸附等温线符合Langmuir 模型, 属于单层吸附, 具有最大介孔比表面积的MCM-41对正丁醛的吸附量最大(484 mg·g^-1). 最后将SBA-15添加到卷烟滤嘴中, 实验结果表明, SBA-15能显著降低卷烟烟气中巴豆醛的释放量.     

Studies on the removal of phosphate in water through adsorption using a novel Zn-MOF and its derived materials

A novel zinc-based metal–organic framework, {[Zn₃(atz)₂(pda)₂]·2(H₂O)}_n (Zn-MOF; Hatz is 5-aminote-1H-terazole; H₂pda is malonic acid), was prepared using the solvothermal method. Carbonization of the prepared Zn-MOF was conducted under elevated temperatures to investigate its phosphate adsorption performance. Through pre-adsorption experiments, the optimal carbonization temperature of 500 °C was determined, yielding Zn-MOF-500. Besides, multiple characterization methods were used to analyze the properties of Zn-MOF and Zn-MOF-500 materials before and after the adsorption of phosphate ions. The results showed that the BET surface area of Zn-MOF-500 was 18.57 m²/g, which was 16.37 times larger than that of the BET surface area of Zn-MOF. At 25 °C, Zn-MOF and Zn-MOF-500 exhibited an adsorption capacity of 123.44 and 226.07 mg/g, respectively. Based on the adsorption isotherms and the adsorption kinetics, the adsorption of PO₄^3- occurs via monolayer. X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS) analysis showed that P was adsorbed on Zn-MOF and Zn-MOF-500 as the zinc hydrogen phosphate and zinc phosphate ions, respectively.     

有序介孔二氧化硅对正丁醛的吸附性能

合成了一系列具有不同孔结构与性质的有序介孔二氧化硅材料SBA-15、MCM-41、SBA-16、KIT-6,同时通过改变水热温度制备了不同孔径大小的SBA-15,并利用小角X射线散射、透射电镜、扫描电镜和氮气吸附-脱附等手段,对其介孔结构进行了表征.以正丁醛为探针分子,考察了其对有机醛的吸附,并与Y-沸石的吸附性能做了对比.结果表明,材料的介孔比表面积与其对正丁醛的吸附量成正比,吸附等温线符合Langmuir模型,属于单层吸附,具有最大介孔比表面积的MCM-41对正丁醛的吸附量最大(484 mg·g-1).最后将SBA-15添加到卷烟滤嘴中,实验结果表明,SBA-15能显著降低卷烟烟气中巴豆醛的释放量.     

磷酸铝吸附除水中氟的研究

采用静态吸附法研究了比表面为308m2/g的无定形磷酸铝吸附除氟性能,研究了接触时间、pH值、吸附剂量等对吸附的影响。结果表明,磷酸铝吸附除氟高效、迅速,30min内可以接近最大吸附量。对含氟50mg/g的溶液,优化条件下的最大除氟率约93%。研究了吸附与溶液pH的关系,得到了优化pH值并解释了吸附机理。吸附的最佳pH值约为5.5。用拟二级动力学方程描述了吸附速率并计算了速率常数。用Langmuir方程拟合了吸附等温线,计算的饱和吸附量为53.5mg/g。吸附剂量对分配系数的影响表明吸附剂表面是不均匀的。     

Optimization Studies of Porous Carbon Preparation from Oil Shale Using Response Surface Methodology and Its Application for Phenol Adsorption

This paper discusses the elaboration of adsorbents from oil shale. The experimental designs a response surface methodology(RSM), which has been applied to optimize the significant preparation factors, such as temperature, time, and the activating agent percentage. The results obtained from central composite design(CCD) revealed that the interaction between the factors was significant for the maximum quantity of adsorption(response). Planned results have shown that a maximum quantity of adsorption for methylene blue is 65 mg/g, which could be achieved with a temperature of 275℃ over 2 h and a percentage of the activating agent of 45%. The predicted values agreed with the experimental finding, with a determination coefficient(R²) of 0.96. The model has been validated by experiments after conditions optimization. The new material(RHO) was characterized by cation exchange capacity, zero charge pH, surface functions, X-ray fluorescence, specific surface area, and electron microscopy analysis. Phenol adsorption was determined using Langmuir, Freundlich and Temkin, which were used to describe the adsorption isotherms. The adsorption capacity of the material was about 263 mg/g, and the kinetic studies showed rapid adsorption.     

Efficient Removal of Cobalt(II) and Strontium(II) Metals from Water using Ethylene Diamine Tetra‐acetic Acid Functionalized Graphene Oxide

Graphene oxide (GO) with high specific surface area was prepared and functionalized with ethylene diamine tetra‐acetic acid (EDTA). The as‐prepared GO and the functionalized one (GO‐EDTA) were characterized using high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), and Raman spectroscopy. The as‐prepared and EDTA funcationalized GO were applied as adsorbent to remove strontium(II) and cobalt(II) from water. The results indicated that the prepared materials are efficient adsorbents for strontium(II) and cobalt(II) removal. The adsorption of Co^II and Sr^II under effects of contact time, temperature, and pH was investigated It is concluded that the maximum adsorption capacities of GO for Co^II and Sr^II were about 168 and 140 mg · g^–1, whereas of GO‐EDTA the values were about 197 and 158 mg · g^–1, respectively. It is indicated that pH 6 and temperature 40 °C are the best condition for Co^II and Sr^II removal from water. The application of Langmuir and Freundlich isotherms indicated that Langmuir isotherm is best fit for Co^II and Sr^II equilibrium adsorption. Adsorption kinetics were studied by applying pseudo first‐order, pseudo second‐order, and intraparticle diffusion models on the experimental data. The results proved that pseudo second‐order model is the best represented adsorption kinetics. Appling the intraparticle diffusion regressions on the experimental data indicated that intraparticle diffusion involved in adsorption process, which was not the only rate‐controlling step.     

Removal of Cr (VI) from aqueous solution using magnetic biochar synthesized by a single step method

Magnetic biochar, as an adsorbent, was synthesized by a single step method, where iron salt was directly mixed with pinewood sawdust by chemical co-precipitation and subsequently pyrolyzed at 700°C for Cr (VI) removal from aqueous solution. The effects of some important parameters including adsorbent dosage (0.4–2.8?g/L), pH (1–10) of the solution, contact time (0–1440 minutes), initial concentration (30–120?mg/L), and temperature (20–40°C) were investigated in batch experiments. Both pre- and post-adsorbents were characterized by SEM-EDX and XPS to investigate the adsorption mechanism. The maximum adsorption capacity of the tested magnetic biochar under the certain experimental conditions determined as optimal was 42.7?mg/g for Cr (VI). The adsorption data were proved to be suitable for the pseudo-second order model for kinetics and the Langmuir model for isotherms with correlation R²?=?0.9996 andR²?>?0.9980, respectively, after fitting with four kinetic models (pseudo-first order, pseudo-second order, W-M model, and Elovich) and three isotherm models (Langmuir, Freundlich, and Temkin). The characteristic analyses further verified that the efficient particle was a mixture of iron oxides in essence, and it had a strong effect on the spontaneous and endothermic adsorption process.     

Synthesis and characterization of silica gel from siliceous sands of southern Tunisia

The present work aimed to achieve valorization of Albian sands for the preparation of sodium silicates that are commonly used as a precursor to prepare silica gel. A siliceous sand sample was mixed with sodium carbonate and heated at a high temperature (1060 °C) to prepare sodium silicates. The sodium silicates were dissolved in distilled water to obtain high quality sodium silicate solution. Hydrochloric acid was then slowly added to the hydrated sodium silicates to obtain silica gel. The collected raw siliceous sands, as well as the prepared silica gels, were characterized by different techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (DSC). XRF confirmed that the detrital sand deposits of southern Tunisia contain high amounts of silica, with content ranging from 88.8% to 97.5%. The internal porosity varied between 17% and 22%, and the specific surface area was less than 5 m²/g. After the treatment described above, it was observed that the porosity of the obtained silica gel reached 57% and the specific surface area exceeded 340 m²/g. Nitrogen adsorption isotherms showed that the prepared silica gels are microporous and mesoporous materials with high adsorption capacities. These results suggest that the obtained silica gels are promising materials for numerous environmental applications.     

硅胶表面上脂肪酸蒸气吸附膜

应用Gibbs方程由甲酸、乙酸和丙酸蒸气在硅胶上的吸附等温线计算了吸附膜的表面压力(π)与每个吸附分子所占面积(σ)间的关系(π～σ图).所得曲线与不溶物在溶液表面上的结果相似,均表现出有“液态扩张膜”“转变膜”和“液态凝聚膜”.不同的是,不溶物只能形成单分子层膜,而硅胶表面上的脂肪酸吸附膜则是多分子层的.蒸气吸附膜由单层向多层的转变,恰与π～σ图上的“液态扩张膜”向“转变膜”的转变相对应.吸附焓(△H)与吸附熵(△S)的计算结果表明,在此转变附近AH和AS发生急剧变化.