聚丙烯酸钠包覆Fe3O4磁性交联聚合物的制备及其对Pb(Ⅱ)和Cd(Ⅱ)的吸附性能

采用溶液分散聚合和Ca²⁺表面交联制备了聚丙烯酸钠包覆Fe₃O₄的磁性交联聚合物（CPAANa@Fe₃O₄）,对其进行了XRD、FT-IR、SEM和TGA等表征。以CPAANa@Fe₃O₄为吸附剂研究了CPAANa@Fe₃O₄对水溶液中Pb²⁺、Cd²⁺的静态吸附,考察了溶液pH、吸附剂投加量、金属离子初始浓度对吸附的影响。结果表明：CPAANa@Fe₃O₄在pH 2～6范围内均具有较好的吸附性能,当吸附剂投加量分别为1.0 g·L^-1和1.6 g·L^-1时对初始浓度分别为200 mg·L^-1的Pb²⁺和100 mg·L^-1的Cd²⁺的去除率达到最大,可使Pb²⁺实现达标排放（GB 8978-1996）;CPAANa@Fe₃O₄对Pb²⁺和Cd²⁺的吸附动力学符合准二级模型,吸附等温线符合Langmuir模型,对Pb²⁺和Cd²⁺的最大吸附量分别为454.55 mg·g^-1和275.48 mg·g^-1。将CPAANa@Fe₃O₄用于处理实际电解矿浆废水,发现能有效吸附其中的Pb²⁺和Cd²⁺,具有潜在实用价值。     

Removal of Cd（II） by Nanometer AIO（OH） Loaded on Fiberglass with Activated Carbon Fiber Felt as Carrier

A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.     

Removal of lead and cadmium ions by single and binary systems using phytogenic magnetic nanoparticles functionalized by 3-marcaptopropanic acid

The present research study is focused on green fabrication of superparamagnetic Phytogenic Magnetic Nanoparticles(PMNPs), and then its surface functionalization with 3-Mercaptopropionic acid(3-MPA). The resulting material(i.e. 3-MPA@PMNPs) characterized by FTIR, powder XRD, SEM, TEM, EDX, VSM, BET and TGA techniques and then further employed for the investigation of the adsorptive removal of lead(Pb~(2+)) and cadmium(Cd~(2+)) ions from aqueous solutions in single and binary systems. The material showed fastest adsorptive rate(98.23%) for Pb~(2+) and(96.5%) Cd~(2+)within the contact time of 60 min at pH 6.5 in the single system. The experimental data were fitted well to Langmuir isotherm, indicated monolayer adsorption of both metal ions onto 3-MPA@PMNPs and an estimated comparable adsorptive capacity of 68.41 mg·g~(-1)(Pb~(2+)) and 79.8 mg·g~(-1)(Cd~(2+)) at p H 6.5. However, kinetic data agreed well with pseudo-second-order model, and indicated that the removal mainly supported chemisorption and/or ion-exchange mechanism. Thermodynamic parameters such asΔGo, ΔHo, and ΔSo, were-3259.20, 119.35 and 20.73 for Pb2+, and-1491.10, 45.441 and 7.87 for Cd~(2+) at temperature 298.15 K, confirmed that adsorption was endothermic, spontaneous and favorable. The material demonstrated higher selectivity of Pb~(2+) and its removal efficiency was(98.20 ± 0.3)% in binary system experiments. The material persisted performance up-to seven(07) consecutive treatment cycles without losing their stability and offered comparable fastest magnetic separation(35 s) from aqueous solutions. Therefore, it is recommended that the prepared material can be employed to remove toxic heavy metal ions from water/wastewaters and this "green" method can easily be implemented at large scale in low economy countries.     

生物除磷颗粒污泥去除Pb2+的效能机制

以好氧颗粒污泥的吸附作用和磷酸盐对重金属的螯合作用为基础,采用富含磷酸盐的生物除磷颗粒污泥作为吸附剂来处理含铅废水,考察了不同吸附条件（pH、Pb²⁺的初始浓度、吸附反应时间）下,颗粒污泥对Pb²⁺的去除效果。结果表明,除磷颗粒污泥在pH为4,初始Pb²⁺浓度为150 mg·L^-1时,对铅的去除率最高（为99.9%）;在吸附反应20 min时即可达到吸附平衡。生物除磷颗粒污泥对Pb²⁺的吸附可以用Langmuir模型拟合（R²=0.993）,最大吸附量为49.5 mg·g^-1。其中离子交换和磷酸盐与Pb²⁺的螯合作用对除磷颗粒污泥去除Pb²⁺起到重要作用;傅里叶变换红外光谱（FTIR）测定表明-COOH、-OH、磷酰基等多种官能团也参与了除磷颗粒污泥除Pb²⁺过程。     

Lead removal from aqueous medium using fruit peels and polyaniline composites in aqueous and non-aqueous solvents in the presence of polyethylene glycol

In the present study, composites of Polyaniline and some fruit peels were synthesized in various conditions and used for lead removal from aqueous solutions. Adsorption tests were conducted in batch mode using the most efficient adsorbent, and the effects of medium pH, initial lead concentration, contact time, adsorbent dosage, and adsorption isotherms were investigated. The results showed that all composites were more efficient in lead removal compared to the fruit peels alone. The highest removal percentage was related to the composite of banana peel and Polyaniline that synthesized in the aqueous solution in the presence of 2 g·L^-1 Poly ethylene glycol. This composite showed 95.96% lead adsorption at pH = 6, the contact time of 90 min, the initial lead concentration of 25 mg·L^-1, and an adsorbent concentration of 8 g·L^-1. Adsorption isotherm study showed that adsorption of lead by synthesized composite could be fitted by both Langmuir and Freundlich models, but the Langmuir model was more fitted than Freundlich. Besides, some characteristics of the composites, such as chemical composition (XRD analysis), structure, and morphology (SEM analysis) and functional groups (FTIR analysis), were studied.     

牛血清白蛋白纳米球接枝杨梅单宁的制备以及吸附去除水体中Pb2+的性能

采用去溶剂法和杨梅单宁-戊二醛固化接枝制备得到杨梅单宁（BT）接枝牛血清白蛋白（BSA）纳米球（BSA-BT-NSs）吸附材料，并系统探讨了其在不同吸附条件下对水体中Pb²⁺的吸附去除性能。研究结果表明：50%用量杨梅单宁（基于BSA-NSs量）接枝固化得到的BSA-BT-NSs具有较好的球形结构和良好的分散性。在吸附实验中，Pb²⁺初始浓度为250mg/L、pH 5.0、温度为298K 条件下吸附20min，BSA-BT-NSs（0.4g/L）对Pb²⁺的吸附效果最佳，最大吸附容量为76mg/g，优于多数同类型吸附材料。BSA-BT-NSs对Pb²⁺吸附过程符合Langmuir方程和准二级吸附动力学模型，且吸附后的BSA-BT-NSs经0.1mol/L 硝酸进行解吸取得了92.04％的良好解吸效果，并可再次重复使用。进一步分析其Pb²⁺吸附机理，表明BSA-BT-NSs中的氨基氮原子、羟基和羧基氧原子作为电子供体参与了与Pb²⁺的空轨道发生配位作用。     

Faujasite zeolite decorated with cobalt ferrite nanoparticles for improving removal and reuse in Pb2+ ions adsorption

Water pollution caused by heavy metals ions has been gaining attention in recent years, increasing the interest in the development of methodologies for their efficient removal focusing on the adsorption process for these purposes. The current challenge faced by adsorption processes is the adequate adsorbent immobilization for removal and reuse. Thus, the present work aimed at producing a faujasite zeolite nanocomposite decorated with cobalt ferrite nanoparticles for Pb~(2+) ions adsorption in an aqueous medium improving magnetic removal and reuse.As a result, a high surface area(434.4 m~2·g~(-1)) for the nanocomposite and an 18.93 emu·g~(-1) saturation magnetization value were obtained, indicating magnetic removal in a promising material for adsorption process. The nanocomposite regeneration capacity evaluated by magnetic recovery after 24 h suspension presented a high Pb~(2+) ion adsorptive capacity(98.4%) in the first cycle. Around 98% of the Pb~(2+) ions were adsorbed in the second cycle. In this way, the synthesized faujasite:cobalt ferrite nanocomposite reveals itself as a promising alternative in adsorption processes, aiming at a synergic effect of FAU zeolite high adsorptive activity and the cobalt ferrite nanoparticles magnetic activity, allowing for adsorbent recovery from the aqueous medium via magnetic force and successive adsorptive cycles.     

Removal of Reactive Red 198 from aqueous solution by combined method multi-walled carbon nanotubes and zero-valent iron:Equilibrium,kinetics, and thermodynamic

Dyes often include toxic,carcinogenic compounds and are harmful to humans' health.Therefore,removal of dyes from textile industry wastewater is essential.The present study aimed to evaluate the efficiency of the combination of zero valent iron(ZVI) powder and multi-walled carbon nanotubes(MWCNTs) in the removal of Reactive Red 198(RR198) dye from aqueous solution.This applied research was performed in a batch system in the laboratory scale.This study investigated the effect of various factors influencing dye removal,including contact time,p H,adsorbent dose,iron powder dose,initial dye concentration,and temperature.The equilibrium adsorption data were analyzed using three common adsorption models:Langmuir,Freundlich and Temkin.Besides,kinetic and thermodynamic parameters were used to establish the adsorption mechanism.The results showed,in pH =3,contact time = 100 min,ZVI dose = 5000 mg·L~(-1),and MWCNTs dose = 600 mg·L~(-1)in 100 mg·L~(-1)dye concentration,the adsorption efficiency increased to 99.16%.Also,adsorption kinetics was best described by the pseudo-second-order model.Equilibrium data fitted well with the Freundlich isotherm(R2= 0.99).The negative values of ΔG0and the positive value of ΔH0(91.76) indicate that the RR198 adsorption process is spontaneous and endothermic.According to the results,the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.     

Enhanced adsorption of phenol from aqueous solution by carbonized trace ZIF-8-decorated activated carbon pellets

Trace zeolitic imidazolate framework-8(ZIF-8)-decorated activated carbon(AC) pellets were synthesized by a facile wet impregnation technique. After pyrolysis of the above composite material, the obtained carbon had a large surface area and pore volume, with traces of Zn on its surface. Subsequently, the capacity of the ZIF8/AC samples to adsorb and remove phenol from aqueous media was evaluated in both batch and column experimental setups. The equilibrium adsorption capacity reached 155.24 mg·g~(-1), which was 2.3 times greater than that of the pure AC(46.24 mg·g~(-1)). In addition, adsorption kinetics were examined by pseudofirst and pseudosecond order models, and adsorption isotherms were fitted into Langmuir and Freundlich equations. The adsorbent could be easily filtered from the solution and washed with methanol and water, while maintaining an efficiency N 90% after 4 cycles. The above results make it a potentially reusable candidate for water purification.     

Adsorptive removal of tetracycline from water using Fe (III)-functionalized carbonized humic acid

Humic acid (HA) was carbonized at 300, 400 and 500 ℃ and then functionalized with 1 wt%-12 wt% Fe(III) respectively [CHA300/400/500-Fe(III)]. Adsorption of such Fe(III)-functionalized carbonized HA as adsorbents to aqueous tetracycline (TC: 25 mg·L^-1) was studied. The adsorption equilibrium time for CHA400-Fe(III) to TC was 6 h faster and the adsorption removal efficiency (R_e) was two times higher than that of HA/CHA. The adsorption R e of CHA400-Fe(III) loaded 10% iron [CHA400-(10%)Fe(III)] to TC could reach 99.8% at 8 h and still kept 80.6% after 8 cycles. The adsorption kinetics were well fitted to the pseudo-second-order equation and the adsorption isotherms could be well delineated via Langmuir equations(R² > 0.99), indicating that the homogeneous chemical adsorption of TC occurred on the adsorbents. The main adsorption mechanisms of TC were complexation Fe(III) and hydrophobic distribution. Electropositive and electronegative repulsion between TC and CHA400-(10%)Fe(III) at lowly pH(2) and highly pH(8-10) respectively, leaded to the relatively low adsorption capacity and more notable influence of ion concentration. When the pH was between 4 and 8, TC mainly existed in neutral molecules (TCH₂), so the influence of ion concentration was not obvious. The dynamic adsorption results showed that the CHA400-(10%)Fe(III) could continuously treat about 2.4 L TC(27 mg·L^-1) wastewater with the effluent concentration as low as 0.068 mg·L^-1. Our study suggested a broad application prospect of a new, effective, lowcost and environment-friendly adsorbent CHA400-(10%)Fe(III) for treatment of low-concentration TC polluted wastewater.     

水泥浆粉去除废水中铅离子效果及行为研究

水泥浆粉含有可吸附重金属离子的成分,可作为吸附剂来处理重金属离子废水。本文利用硅酸盐水泥制备了不同水化龄期的水泥浆粉来处理含Pb²⁺废水,通过X射线衍射仪、同步热分析仪、电感耦合等离子体发射光谱仪等测试方法,研究了水泥浆粉龄期、浆粉用量、Pb²⁺浓度、pH值、温度、时间对Pb²⁺去除效果及吸附行为的影响。结果表明,水泥浆粉对废水中的Pb²⁺去除率普遍大于80%。在35 ℃、pH=2、吸附时间200 min时,0.04 g水灰比为0.50、水化龄期为60 d的水泥浆粉对初始浓度为700 mg/L的Pb²⁺溶液的Pb²⁺去除率为96.06%,吸附容量为336.22 mg/g。水泥浆粉对Pb²⁺的吸附热力学符合Freundlich吸附等温模型,吸附动力学符合拟一级动力学模型。     

用椰壳制活性炭吸附去除三价铋离子(英文)

In present study,we report the preparation of coconut shell activated carbon as adsorbent and its appli-cation for Bi(Ⅲ) removal from aqueous solutions.The developed adsorbent was characterized with scanning elec-tron microscope(SEM),Fourier Transform Infrared(FTIR),C,H,N,S analyzer,and BET surface area analyzer.The parameters examined include agitation time,initial concentration of Bi(Ⅲ),adsorbent dose and temperature.The maximum adsorption of Bi(Ⅲ)(98.72%) was observed at 250 mg·L-1 of Bi(Ⅲ) and adsorbent dose of 0.7 g when agitation was at 160 r·min-1 for 240 min at(299±2) K.The thermodynamic parameters such as Gibb’s free energy(△Gθ),enthalpy(△Hθ) and entropy(△Sθ) were evaluated.For the isotherm models applied to adsorption study,the Langmuir isotherm model fits better than the Freundlich isotherm.The maximum adsorption capacity from the Langmuir isotherm was 54.35 mg?g?1 of Bi(Ⅲ).The kinetic study of the adsorption shows that the pseudo second order model is more appropriate than the pseudo first order model.The result shows that,coconut shell ac-tivated carbon is an effective adsorbent to remove Bi(Ⅲ) from aqueous solutions with good adsorption capacity.     

Recovery of lithium using H4Mn3.5Ti1.5O12/reduced graphene oxide/polyacrylamide composite hydrogel from brine by Ads-ESIX process

Powdery Li⁺-imprinted manganese oxides adsorbent was widely used to the recovery of Li⁺, but there are some difficulties, such as poor stability in acid solution, inconvenience of operation and separation. In this work, a useful hydrogel composite based H₄Mn_3.5Ti_1.5O₁₂/reduced graphene oxide/polyacrylamide (HMTO-rGO/PAM) was fabricated by thermal initiation method with promising stable, conductive and selective properties. The resulting materials were characterized by field emission scanning electron microscope, infrared absorption spectrum, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical techniques. The recovery of Li⁺ was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process. The adsorption capacity of 51.5 mg·g^-1 could be achieved with an initial Li⁺ concentration of 200 mg·L^-1 in pH 10, at 45 ℃ for 12 h. Li⁺ ions could be quickly desorbed by cyclic voltammetry (CV) in pH 3, 0.1 mol·L^-1 HCl/NH₄Cl accompanying the exchange of Li⁺ and H⁺(NH₄⁺) and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.     

Enhanced adsorptive removal of Cr(VI) in aqueous solution by polyethyleneimine modified palygorskite

Polyethyleneimine (PEI) modified palygorskite (Pal) was used for the adsorption of Cr(VI) in aqueous solution. The absorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterized results confirmed that the Pal has been successfully modified by PEI. The modification of PEI increased the Cr(VI) adsorption performance of the Pal by the adsorption combined reduction mechanism, and amino groups of the adsorbent play the main role in the enhanced Cr(VI) adsorption. The maximum adsorption capacity was 51.10 mg·g^-1 at pH 4.0 and 25 ℃. The adsorption kinetics of Cr(VI) on the adsorbent conforms to the Langmuir isotherm model. The maximum adsorption occurs at pH 3, and then the adsorption capacity of PEI-Pal was decreased with the increase of pH values. The adsorption kinetics of Cr(VI) on PEI-Pal was modeled with pseudo-second-order model. The addition of Cl^-, SO₄^2- and PO₄^3- reduced the Cr(VI) adsorption by competition with Cr(VI) for the active sites of PEI-Pal. The Cr(VI) saturated PEI-Pal can be regenerated in alkaline solution, and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles. The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI) in aqueous solutions.     

Adsorption of methyl orange from aqueous solution by composite magnetic microspheres of chitosan and quaternary ammonium chitosan derivative

Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative (CHMMs) were prepared by inverse suspension method, and used for the methyl orange (MO) removal from aqueous solutions. The CHMMs were characterized by a scanning electron microscope, a transmission electron microscope, and Fourier transform infrared spectroscopy, respectively. Compared with the chitosan beads, the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size. The MO adsorption by CHMMs was investigated by batch adsorption experiments. The adsorption kinetics was conformed to the pseudo second-order kinetics equation. The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K. Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change (ΔH°) of 99.44 kJ·mol^-1. The CHMMs had a stable performance for MO adsorption in the pH range of 4-10, but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction. A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs. The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.     

Stellerite-seeded facile synthesis of zeolite X with excellent aqueous Cd2+ and Ni2+ adsorption performance

Zeolite X was synthesized by a two-step hydrothermal method using natural stellerite zeolite as the silicon seed, and its adsorption performance for Cd²⁺ and Ni²⁺ ions was experimentally and comprehensively investigated. The effects of pH, zeolite X dosage, contact time, and temperature on adsorption performance for Cd²⁺ and Ni²⁺ ions over were studied. The adsorption process was endothermic and spontaneous, and followed the pseudo-second-order kinetic and the Langmuir isotherm models. The maximum adsorption capacitiesfor Cd²⁺ and Ni²⁺ ions at 298 K were 173.553 and 75.897 mg·g^-1, respectively. Ion exchange and precipitation were the principal mechanisms for the removal of Cd²⁺ ions from aqueous solutions by zeolite X, followed by electrostatic adsorption. Ion exchange was the principal mechanisms for the removal of Ni²⁺ ions from aqueous solutions by zeolite X, followed by electrostatic adsorption and precipitation. The zeolite X converted from stellerite zeolite has a low n(Si/Al), abundant hydroxyl groups, and high crystallinity and purity, imparting a good adsorption performance for Cd²⁺ and Ni²⁺ ions. This study suggests that zeolite X converted from stellerite zeolite could be a useful environmentally-friendly and effective tool for the removal of Cd²⁺ and Ni²⁺ ions from aqueous solutions.     

交联氧化铝-壳聚糖新杂化吸附剂的制备及去除废水中Cu(Ⅱ)(英文)

A novel biosorbent was developed by coating chitosan,a naturally and abundantly available biopolymer,on to activated alumina based on oil shale ash via crosslinking.The adsorbent was characterized by various techniques,such as Fourier transform infrared spectroscopy,scanning electron microscopy,thermogravimetric-differential thermal analysis,and X-ray photoelectron spectroscope.Batch isothermal equilibrium adsorption experiments were condcted to evaluate the adsorbent for the removal of Cu(Ⅱ) from wastewater.The effect of pH and agitation time on the adsorption capacity was also investigated,indicating that the optimum pH was 6.0.The equilibrium adsorp-tion data were correlated with Langmuir and Freundlich models.The maximum monolayer adsorption capacity of chitosan coated alumina sorbent as obtained from Langmuir adsorption isotherm was found to be 315.46 mg·g-1 for Cu(Ⅱ).The adsorbent loaded with Cu(Ⅱ) was readily regenerated using 0.1 mol?L?1 sodium hydroxide solution.All these indicated that chitosan coated alumina adsorbent not only have high adsorption activity,but also had good stability in the wastewater treatment process.     

累托石吸附分离水中金霉素(英文)

The removal of antibiotics from water by clay minerals has become the focus of research due to their strong adsorptive ability. In this study, adsorption of chlortetracycline (CTC) onto rectories was conducted and the effects of time, concentration, temperature and pH were investigated. Experimental results showed that adsorption equilibrium was reached in 8 h. Based on the Langmuir model, the maximum adsorption capacity of CTC on rectories was 177.7 mg·g 1 at room temperature. By the study on adsorption dynamics, it is found that the kinetic date fit the pseudo-second-order model well. The adsorption of CTC by rectories is endothermic and the free energy is in the range of 10 to 30 kJ·mol 1 . The pH value of solution has significant effects on adsorption and the optimal pH is at acidity (pH 2-6). At concentration of 2500 mg·L 1 , the intercalated CTC produces an interlayer space with a height of 1.38 nm, which is 1.12 nm in raw rectories, suggesting that the adsorption occurs between layers of rectories.     

氧化铈-二氧化硅介孔材料制备及对铜离子的吸附性能

采用共沉淀法和沉淀浸渍法制备了纳米氧化铈-二氧化硅（CeO₂-SiO₂）介孔材料吸附剂,主要考察了其对水中铜离子（Cu²⁺）的吸附行为。通过X射线衍射（XRD）、扫描电镜（SEM）和氮吸附（BET）等手段对合成的介孔材料进行了性能表征,并通过静态吸附实验分析了溶液pH、溶液初始金属离子质量浓度、吸附剂用量、吸附时间等条件对介孔材料吸附Cu²⁺性能的影响。结果表明：共沉淀法制备的纳米CeO₂-SiO₂介孔材料对Cu²⁺的去除效果较沉淀浸渍法要好;当溶液pH=7.0时CeO₂-SiO₂介孔材料对Cu²⁺的吸附效果最好,20 min时基本达到吸附平衡;溶液初始Cu²⁺浓度增大Cu²⁺去除率降低,Cu²⁺累计吸附量增大;随着吸附剂用量增加Cu²⁺去除率增大,当CeO₂-SiO₂吸附剂用量为0.15 g/L时对Cu²⁺的去除率趋于稳定;CeO₂-SiO₂吸附剂对不同金属离子吸附性能由大到小的顺序为Cu²⁺、Fe²⁺、Mn²⁺,该吸附过程均符合准二级动力学模型。     

Adsorption of Pb, Cu and Cd in FDU-1 silica and FDU-1 silica modified with humic acid

Ordered mesoporous silica with cubic structure, type FDU-1, was synthesized under strong acid media using B-50-6600 poly(ethylene oxide)–poly(butilene oxide)–poly(ethylene oxide) triblock copolymer (EO₃₉BO₄₇EO₃₉) and tetraethyl orthosilicate (TEOS). Humic acid (HA) was modified to the synthesis process at a concentration of 1.5 mmol per gram of SiO₂. Thermogravimetry, small angle X-ray diffraction, nitrogen adsorption and high resolution transmission electron microscopy were used to characterize the samples. The pristine FDU-1 and FDU-1 with incorporated 1.5 mmol of HA were tested for adsorption of Pb²⁺, Cu²⁺ and Cd²⁺ in aqueous solution. Incorporation of humic acid into the FDU-1 silica afforded an adsorbent with strong affinity for Cd²⁺, Cu²⁺ and Pb²⁺ from single ion solutions. Adsorption of Cu²⁺ was significantly enhanced after incorporation of humic acid, a fact that can be explained by the formation of complexes with carboxylic and phenolic groups at low concentrations of the metal cation. The results demonstrated the potential applicability of FDU-1 with incorporated HA in the removal of low concentrations of heavy metal cations from aqueous solution, such as wastewaters, after usual precipitation of metal hydroxides in alkaline medium and proper pH conditioning in the range between 6 and 7.