改性5分子筛吸附剂从含氟水中除氟研究

研究了以5A分子筛为骨架吸附材料,经在含AI^3 或Fe^3 溶液中离子交换改性处理,获得了一种可吸附除氟的改性分子筛。实验表明,该种分子筛对水溶液中的低含量氟有良好的吸附性能。静态饱和吸附容量可达28．98和21．4mgF/g分子筛（分别对含AI^3 或Fe^3 分子筛）。含氟水经分子筛柱处理后,除氟率可达99％。吸附氟后的分子筛可用柠檬酸盐洗脱氟,洗脱率接近安全。洗脱后的分子筛可重复使用。得到一种新的效果显著的除氟方法。     

新型深度除氟改性树脂的制备及其吸附性能研究

以XAD-4为母体自合成了氨基改性和氨基改性后负载金属两种新型深度除氟树脂,并对其进行了理化结构的表征,研究了其吸附特性。结果表明,静态实验中氨基改性的树脂吸附量大于氨基改性并负载金属的树脂。pH值对两种树脂吸附F-的影响均不大。氨基改性的树脂对F-的吸附主要是物理吸附,而氨基改性并负载金属的树脂对F-的吸附主要是化学吸附。两种树脂对F-的吸附均显示出对准二级动力学方程拟合相关性较好。动态实验中,以F-浓度达到1mg/L为穿透点时,氨基改性树脂和氨基改性并负载金属的树脂穿透时间分别为11h和24h。氨基改性树脂对F-的吸附主要通过静电作用进行,而氨基改性并负载金属的树脂对F-的吸附还包括金属与铁离子的络合作用。     

有氧热解改性木屑及其对氟离子的吸附研究

以氯化铝、乙醇及木屑为原料，采用有氧热解法成功制备了一种新型改性木屑吸附剂(SAE)，可用于水中氟化物的吸附去除，对SAE进行了物性表征及其对氟离子的吸附性能评价。结果表明：有氧热解促进半纤维素和部分木质素的消融去除，有利于疏通孔道，增强材料的比表面积和吸附性能；在7.0～9.0的pH范围内，除氟率超过90%；氟吸附等温线符合Langmuir模式，经此模型计算出SAE对氟的最大吸附量为21.7 mg/g。吸附动力学符合Lagergren伪二阶模型(R²>0.99)，表明SAE对氟离子的吸附以化学吸附为主，XPS及FT-IR分析表明该化学吸附主要是氟和铝的结合，也有少量炭和氟的结合。此外，离子交换和静电吸附也对氟离子在SAE上的吸附有贡献。     

原位合成羟基磷灰石/壳聚糖复合吸附剂及除氟特性研究

利用原位共沉淀法合成了羟基磷灰石/壳聚糖复合吸附剂,通过扫描电镜、X射线粉末衍射、红外光谱和N2吸附-脱附曲线,研究复合前后羟基磷灰石的理化特征变化。实验结果表明与壳聚糖复合后羟基磷灰石的晶型并没有改变,只是结晶度有所降低,且复合后表面形成了不规则的凹凸结构,表面粗糙度增加。比表面积从106.75m2/g增加到127.58m2/g。复合吸附剂孔径大部分集中在10~50nm,属于介孔结构。利用Langmuir和Freundlich吸附等温方程对实验数据进行了拟合,对比相关系数R2值,Langmuir模型能更好地描述该吸附过程。复合吸附剂对氟离子的吸附符合拟二级反应动力学方程。计算了吸附热力学和动力学参数值,探讨了复合吸附剂对氟离子的吸附机理。ΔG0<0、ΔH0>0和ΔS0>0,说明复合吸附剂对氟离子的吸附是自发的、吸热的熵增过程,温度升高有利于吸附。吸附活化能(Ea)=15.03kJ·mol-1,迁移能(E)=7.639kJ·mol-1,说明该吸附过程以物理吸附为主。     

La-金属有机骨架化合物的制备及其除氟性能研究

采用水热合成法制备La-MOFs吸附剂,通过扫描电镜、红外光谱、X-射线粉末衍射和N2吸附-脱附曲线对La-MOFs吸附剂的结构和形貌进行表征,并研究其对水溶液中氟离子的吸附特性.La-MOFs吸附剂为毛线团状球形结构,最可几孔径为15.84nm,比表面积为16.95m2/g.吸附氟离子后形成了氟化镧晶体.考察了硝酸镧...     

稀土吸附剂城市污水深度除磷

采用以分子筛为载体、负载镧制成复合吸附剂对城市污水进行深度除磷.实验结果表明:研制的稀土吸附剂适于处理弱酸性废水.对于城市污水含磷浓度为1.0 mg·L-1,当pH值3～7,吸附剂的投加量在0.06 g·L-1,吸附3 h时,磷的去除率可达99.5%,出水pH值在6.0～8.5之间.     

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。     

WBC-Fe的制备及其除氟性能

采用高温热解法制备铁改性的梧桐叶生物炭(WBC-Fe)并优化制备工艺,同时使用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和EDS能谱对材料进行表征。通过静态吸附实验,将该材料用于含氟模拟废水的实验研究。结果表明：以F^-吸附量为主要指标,WBC-Fe的最佳制备工艺为氯化铁浓度1 mol/L、热解温度400℃、热解时间1 h;该材料含有较丰富的含氧官能团,且表面有铁元素成功负载;当F^-溶液初始浓度为11.80 mg/L、pH值为6.5、温度为30℃、投加量为3 g/L、吸附时间为4 h时,F^-在该材料表面的吸附达到平衡,此时F^-吸附量为3.70 mg/g,是未改性生物炭(WBC)的7倍。Langmuir模型、二级动力学方程能较好的描述F^-在WBC-Fe表面的吸附行为,表明其对F^-的吸附以单层吸附为主,且受化学作用控制,可能是该材料表面负载的三价铁与F^-之间存在较好配位作用的结果。     

负载钛水合氧化物球状吸附剂的孔结构及其对氟离子吸附性能…

以大孔吸附树脂为基体，用Ｔｉ（ｎ－ＯＣ４Ｈ９）４浸渍基体树脂后，在一定条件下使该醇盐水解，制得由钛水合氧化物负载的球状吸附剂。本文研究了这种吸附剂的孔结构及其对氟离子的吸附性能。     

碳纳米管负载氧化铝材料的制备及其吸附水中氟离子的研究

采用碳纳米管和硝酸铝制备了碳纳米管负载氧化铝新型除氟材料.X射线衍射检测发现,当焙烧温度低于850℃时,氧化铝为无定形态,当焙烧温度为1050℃时,氧化铝为α形态,扫描电子显微镜观察到碳纳米管与氧化铝均匀掺杂.同时用碳纳米管负载氧化铝复合材料进行水中氟离子的吸附研究,结果表明,该复合材料具有优良的除氟效能.氧化铝负载量为30%、焙烧温度为450℃条件下制备的碳纳米管负载氧化铝复合材料的吸附除氟能力是γ-氧化铝的2.0～3.5倍,与IRA-410聚合树脂的吸附除氟能力相当,适宜pH范围为5.0～9.0,吸附等温线符合Freundlich方程.     

氧化铁改性蛭石的制备、表征及吸附氟的特性

采用共沉淀法制备了3种不同含铁量的氧化铁改性蛭石（Verm-Fe_x,x=5,10,20）,研究了纯蛭石（Verm）和Verm-Fe_x的表面性质及吸附氟的特性。与样品Verm比较,3种Verm-Fe_x中Verm的d_（002）层间距略有升高;Verm-Fe_x的孔体积、表面积、表面分形度均随含铁量的增加而升高,其中微孔体积和外表面积的增加幅度更明显。4种样品的等电点（IEP）也随含铁量的增加而明显升高;初始pH＝5.0时,它们的表面ζ电位分别为-16.4,-6.1,10.5和28.4 mV。4种样品对氟的等温吸附数据用单吸附位Langmuir模型拟合（R²=0.973~0.995）时,Verm的R²最高;双吸附位Langmuir模型可很好地描述3种Verm-Fe_x样品的等温吸附过程（R²=0.991~0.998）;Freundlich模型对4种样品吸附数据的拟合度较差（R²=0.835~0.937）,但R²随样品含铁量的增加而略微升高。初始pH=5.0时,Verm和Verm-Fe_x（x=5,10,20）对氟的最大吸附容量（q_max）分别为3.18,6.76,9.27和12.43 mg·g^-1。可见,Verm-Fe_x（尤其含铁量较高的产物）对表生环境中氟的吸附固定性能明显高于Verm。     

氧化铁改性蛭石的制备、表征及吸附氟的特性

采用共沉淀法制备了3种不同含铁量的氧化铁改性蛭石(Verm-Fe_x,x=5,10,20),研究了纯蛭石(Verm)和Verm-Fe_x的表面性质及吸附氟的特性。与样品Verm比较,3种Verm-Fe_x中Verm的d₍₀₀₂₎层间距略有升高;Verm-Fe_x的孔体积、表面积、表面分形度均随含铁量的增加而升高,其中微孔体积和外表面积的增加幅度更明显。4种样品的等电点(IEP)也随含铁量的增加而明显升高;初始pH＝5.0时,它们的表面ζ电位分别为-16.4,-6.1,10.5和28.4 mV。4种样品对氟的等温吸附数据用单吸附位Langmuir模型拟合(R²=0.973~0.995)时,Verm的R²最高;双吸附位Langmuir模型可很好地描述3种Verm-Fe_x样品的等温吸附过程(R²=0.991~0.998);Freundlich模型对4种样品吸附数据的拟合度较差(R²=0.835~0.937),但R²随样品含铁量的增加而略微升高。初始pH=5.0时,Verm和Verm-Fe_x(x=5,10,20)对氟的最大吸附容量(q_max)分别为3.18,6.76,9.27和12.43 mg·g^-1。可见,Verm-Fe_x(尤其含铁量较高的产物)对表生环境中氟的吸附固定性能明显高于Verm。     

铝掺杂针铁矿的制备、表征及吸附氟的特性

水热条件下制备了针铁矿(Goe)和几种铝掺杂针铁矿(Goe-Al_(0.1),Goe-Al_(0.2)和Goe-Al_(0.4)),用X射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对样品进行了表征,并研究了它们对氟离子的吸附特性。结果表明,随着铝掺杂量的增加,铝掺杂针铁矿的结晶度不断减弱、颗粒的长度不断减小。4种样品的微孔表面积、孔体积和表面分形度都表现为GoeGoeAl0.1Goe-Al_(0.2)Goe-Al_(0.4),而孔径分布表现为相反的顺序。Goe、Goe-Al_(0.1)、Goe-Al_(0.2)和Goe-Al_(0.4)的电荷零点(PZC)分别为8.2、8.3、8.5和8.7,pH=5.0时它们的表面电荷量分别为0.66、0.83、1.03和1.19 mmol·g~(-1)。准二级动力学模型适合描述4种样品对氟的吸附动力学过程,表明化学吸附是主要作用机制。一位Langmuir模型可较好的拟合等温吸附数据(R2为0.967~0.981),二位Langmuir模型对等温吸附数据的拟合度更高(R2为0.982~0.995),而Freundlich模型的拟合度较低(R2为0.877~0.912)。初始pH=5.0时,Goe、Goe-Al_(0.1)、Goe-Al_(0.2)和Goe-Al_(0.4)对氟的最大吸附容量分别为8.83、10.24、11.72和12.86 mg·g~(-1)。可见,铝掺杂针铁矿对土-水环境中氟的吸附容量高于纯针铁矿。     

铝掺杂针铁矿的制备、表征及吸附氟的特性

水热条件下制备了针铁矿（Goe）和几种铝掺杂针铁矿（Goe-Al_0.1,Goe-Al_0.2和Goe-Al_0.4）,用X射线衍射（XRD）、扫描电镜（SEM）、氮气物理性吸附、酸碱滴定等手段对样品进行了表征,并研究了它们对氟离子的吸附特性。结果表明,随着铝掺杂量的增加,铝掺杂针铁矿的结晶度不断减弱、颗粒的长度不断减小。4种样品的微孔表面积、孔体积和表面分形度都表现为Goe < Goe-Al_0.1 < Goe-Al_0.2 < Goe-Al_0.4,而孔径分布表现为相反的顺序。Goe、Goe-Al_0.1、Goe-Al_0.2和Goe-Al_0.4的电荷零点（PZC）分别为8.2、8.3、8.5和8.7,pH=5.0时它们的表面电荷量分别为0.66、0.83、1.03和1.19 mmol·g^-1。准二级动力学模型适合描述4种样品对氟的吸附动力学过程,表明化学吸附是主要作用机制。一位Langmuir模型可较好的拟合等温吸附数据（R²为0.967~0.981）,二位Langmuir模型对等温吸附数据的拟合度更高（R²为0.982~0.995）,而Freundlich模型的拟合度较低（R²为0.877~0.912）。初始pH=5.0时,Goe、Goe-Al_0.1、Goe-Al_0.2和Goe-Al_0.4对氟的最大吸附容量分别为8.83、10.24、11.72和12.86 mg·g^-1。可见,铝掺杂针铁矿对土水环境中氟的吸附容量高于纯针铁矿。     

Characterization and Applications of Red Mud,an Aluminum Industry Waste Material,in the Construction and Building Industries,as well as Catalysis

The disposal of red mud (RM), a waste material generated by the aluminum industry, remains a global environmental concern because of its high alkalinity and smaller particle size, which have the potential to pollute air, soil, and water. Recently, efforts have been made to develop a strategy for reusing industrial byproducts, such as RM, and turning waste into value-added products. The use of RM as (i) a supplementary cementitious material for construction and building materials, such as cement, concrete, bricks, ceramics, and geopolymers, and (ii) a catalyst is discussed in this review. Furthermore, the physical, chemical, mineralogical, structural, and thermal properties of RM, as well as its environmental impact, are also discussed in this review. It is possible to conclude that using RM in catalysis, cement, and construction industries is the most efficient way to recycle this byproduct on a large scale. However, the low cementitious properties of RM can be attributed to a reduction in the fresh and mechanical properties of composites incorporating RM. On the other hand, RM can be used as an efficient active catalyst to synthesize organic molecules and reduce air pollution, which not only makes use of solid waste but also lowers the price of the catalyst. The review provides basic information on the characterization of RM and its suitability in various applications, paving the way for more advanced research on the sustainable disposal of RM waste. Future research perspectives on the utilization of RM are also addressed.     

Fluoride and lead adsorption on carbon nanotubes

The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on.…     

镧改性的CuHY分子筛中铜离子的分布及其对吸附脱硫性能的影响

在氮气气氛下采用等体积浸渍法制备了载Cu的HY和LaHY分子筛.用x射线衍射(XRD)、N2吸附、氨程序升温脱附和X射线光电子能谱对分子筛进行了表征.通过多晶XRD确定了Cu2+离子在Y型分子筛笼内的结构与分布,并测定了分子筛在含二苯并噻吩(DBT)的模拟柴油中的吸附脱硫性能.结果表明,前驱体CuCl2中的大部分Cu物种与HY和LaHY分子筛进行了离子交换.对于La3+改性的CuHY分子筛(CuLaHY),进入分子筛超笼中的Cu2+离子与骨架氧和水分子配位,牢固地定位于Y型分子筛超笼的SⅡ及SⅢ位;对于CuHY分子筛,超笼中的Cu2+离子只接近于SⅡ及SⅢ位.极少部分CuCl分子高度分散在分子筛笼内,没有定位.处于超笼中SⅡ及SⅢ位的Cu2+离子对模拟柴油中的DBT分子具有吸附作用,是吸附脱硫的活性中心.CuLaHY分子筛的吸附脱硫性能优于CuHY分子筛.当模拟柴油中含有萘时,萘与DBT分子会产生竞争吸附.     

Fixed-Bed Adsorption: Comparisons of Virgin and Zirconium Oxide-Coated Scoria for the Removal of Fluoride from Water

Many people worldwide are exposed to extreme levels of fluoride in drinking water. It is, therefore, critical to develop inexpensive, locally available, and environmentally friendly adsorbents for fluoride-laden water defluoridation. In the current study, virgin scoria (volcanic rock) from Ethiopia, was modified with zirconium oxide and used as an adsorbent in a fixed-bed column aiming at the removal of fluoride from water. The adsorption capability of zirconium oxide-coated scoria (ZrOCSc) was compared with unmodified virgin scoria (VSco). XRD, FTIR, XRF, SEM, ICP-OES, and the pH_PZC tests were evaluated to explore the adsorption mechanisms. Thermal analysis of VSco and ZrOCSc revealed lower total weight losses of 2.3 and 3.2 percent, respectively, owing to the removal of water molecules and OH species linked to metal oxides contained in the material. The effect of test conditions such as the pH of the solution and the influent flow rate on the adsorption capacity of the adsorbent was carefully studied. ZrOCSc exhibited the maximum removal capacity of 58 mg/kg, which was 4.46 times higher than the observations for VSco (13 mg/kg) at pH 2, and an initial flow rate of 1.25 mL/min. Breakthrough time increased with decreasing initial pH and flow rate. The adsorption experimental data under various test conditions were examined by the Thomas and Adams–Bohart models. Both models were found very effective in describing the experimental data with a correlation coefficient (R²) of ≥0.976 (ZrOCSc) and ≥0.967 (VSco). Generally, coating VSco with zirconium oxide improved the adsorption performance of VSco; hence, a ZrOCSc-packed fixed bed could be employed for the decontamination of high levels of fluoride from groundwater. However, further examination of the adsorbent using natural groundwater is advisable to produce a definitive conclusion.     

Optimization of Fluoride Adsorption on Acid Modified Bentonite Clay Using Fixed-Bed Column by Response Surface Method

Using small-scale batch tests, various researchers investigated the adsorptive removal of fluoride using low-cost clay minerals, such as Bentonite. In this study, Column adsorption studies were used to investigate the removal of fluoride from aqueous solution using acid-treated Bentonite (ATB). The effects of initial fluoride concentration, flow rates, and bed depth on fluoride removal efficiency (R) and adsorption capability (qe) in continuous settings were investigated, and the optimal operating condition was determined using central composite design (CCD). The model’s suitability was determined by examining the relationship between experimental and expected response values. The analysis of variance was used to determine the importance of independent variables and their interactions. The optimal values were determined as the initial concentration of 5.51 mg/L, volumetric flow rate of 17.2 mL/min and adsorbent packed-bed depth of 8.88 cm, with % removal of 100, adsorptive capacity of 2.46 mg/g and desirability of 1.0. This output reveals that an acid activation of Bentonite has made the adsorbent successful for field application.     

氨基硅烷偶联剂改性凹凸棒土的制备及其吸附性能

采用双氨基硅烷偶联剂KH-792对盐酸改性凹凸棒土(HATT)进行改性,使用FTIR、TGA、DSC、XRD和BET等对目标产物(KHATT)进行了表征。 研究了KHATT对模拟水样中Cr(Ⅵ)的吸附性能,系统考察了模拟水样中Cr(Ⅵ)的初始浓度、pH值、吸附时间及KHATT用量等因素对Cr(Ⅳ)去除率的影响。 结果表明,在KHATT用量为3 g/L、吸附时间为40 min、pH值为5.5的条件下,KHATT对Cr(Ⅵ)的去除率最高,达85.15%;且KHATT经再生后第4次的吸附量仍可达到第1次吸附量的90%以上。 对吸附的过程和机理进行了初步探讨。