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1.
nSiO_2纳米颗粒是一种广泛应用的工程纳米材料,为增加其对水溶液中Cd~(2+)的吸附性能,采用接枝改性的方法制备出乙二胺四乙酸(EDTA)改性nSiO_2纳米颗粒(EDTA-nSiO_2),并用透射电镜、氮气吸附-解吸、红外光谱和差热分析等手段对其进行了结构表征,同时以其为吸附剂,通过批处理实验法探讨了体系pH、吸附时间、温度、离子强度等因素对Cd~(2+)吸附的影响,并结合X射线能谱(XPS)分析对其吸附机制进行了分析.结果表明,以EDTA为改性剂,可以成功制备出稳定性良好的EDTA-nSiO_2纳米颗粒,其对Cd~(2+)的吸附受体系p H控制;nSiO_2对Cd~(2+)的吸附量较小,EDTA改性可增加nSiO_2对Cd~(2+)的吸附作用,随着p H的升高,Cd~(2+)的吸附效果逐渐增强,在p H大于4.0后逐渐趋于稳定.EDTA-nSiO_2对Cd~(2+)的吸附速率较快,可在1 h内达到吸附平衡.EDTA-nSiO_2对Cd~(2+)的吸附为吸热的自发过程,吸附等温线可用Langmuir模型描述.NaCl浓度增加会导致Cd~(2+)的吸附量下降,当体系Na Cl浓度从0增加到100 mmol·L~(-1),Cd~(2+)的最大吸附量从0.433 mmol·g-1降低至0.294mmol·g-1.0.1 mol·L~(-1)HCl是较为合适的吸附剂再生液,Cd~(2+)洗脱率约94.36%.结合pH、温度、离子强度、再生和XPS分析结果,可以推测出EDTA-nSiO_2对Cd~(2+)的吸附是包含有简单的物理吸附和离子交换过程,并以化学络合为主的吸附过程.EDTA-nSiO_2是一种对水体Cd~(2+)具有较好吸附能力的工程纳米材料吸附剂.  相似文献   

2.
以金属有机骨架材料MIL-68(Al)为吸附剂,探究其对水中典型荧光增白剂VBL分子的吸附行为.采用粉末X射线衍射仪(XRD)、傅里叶变换红外光谱(FTIR)、场发射扫描电镜(SEM)及N_2吸附脱附对MIL-68(Al)的结构性质进行表征.探讨了p H值、离子强度、污染物初始浓度、反应温度及吸附时间对MIL-68(Al)吸附去除水中VBL的影响,并对吸附等温线、动力学、热力学及吸附机制进行了分析.实验结果表明,MIL-68(Al)对VBL的吸附能适应较宽的p H范围,吸附等温线符合Langmuir模型,最大吸附容量达到400.02 mg·g~(-1);吸附速率在前20 min很快,并且能在180 min达到吸附平衡,吸附动力学符合准二级动力学模型;吸附过程是吸热反应,吸附自发进行并且主要由熵驱动;静电作用和氢键作用对吸附均有贡献,静电作用是吸附发生的主要机制.由以上结果可知,MIL-68(Al)是一种潜在的高效吸附剂,在去除水中的VBL分子方面极具潜力.  相似文献   

3.
Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb(Ⅱ) and Cd(Ⅱ) adsorption. The microspheres were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb(Ⅱ) and Cd(Ⅱ) than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb(Ⅱ) and Cd(Ⅱ), respectively, implying that adsorption processes involved monolayer adsorption. Pb(Ⅱ) and Cd(Ⅱ) adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb(Ⅱ)- and Cd(Ⅱ)-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb(Ⅱ) and Cd(Ⅱ) in wastewater treatment processes.  相似文献   

4.
The fluoride ion removal from aqueous solution using synthesized Mg-Cr-Cl layered double hydroxide has been reported.Mg-Cr-Cl was characterized by X-ray powder diffraction,Fourier-transform infrared,thermo-gravimetric analysis,differential thermal analysis,and scanning electron microscope.Adsorption experiments were carried out in batch mode as a function of adsorption dosages,contact time,pH,and initial fluoride concentration to get optimum adsorption capacity.The adsorption kinetic study showed that the adsorption process followed first order kinetics.The fluoride removal was 88.5% and 77.4% at pH 7 with an adsorbent dose of 0.6 g/100 mL solution and initial fluoride concentration of 10 mg/L and 100 mg/L,respectively.The equilibrium was established at 40 min.Adsorption experiment data were fitted well with Langmuir isotherm with R 2 = 0.9924.Thermodynamic constants were also measured and concluded that the adsorption process was spontaneous and endothermic in nature.The removal percentage decreased slowly with increasing pH.This process is suitable for industrial effluents.The regeneration of the material is not possible.  相似文献   

5.
La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4 , and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.  相似文献   

6.
重金属离子废水会对人体健康和环境造成严重威胁,吸附法是去除重金属废水中重金属离子的重要方法.对凹凸棒土(ATP)接枝磁性Fe3O4纳米粒子,再使用3-氨基丙基三乙氧基硅烷(APTES)进行改性,制备了具有良好吸附性能的凹凸棒复合纳米材料吸附剂(ATP-Fe3O4-APTES),并将其用于重金属离子废水的处理.利用FT-IR、XRD、SEM及TEM、BET吸脱附法、Zeta电位和VSM分析等方法对材料的结构和表面性质进行了分析表征.研究了所制备材料对重金属离子Pb2+的吸附行为,考察了溶液pH、吸附时间、吸附温度和Pb2+初始浓度等因素对材料吸附性能的影响作用,探讨了吸附过程的吸附动力学、吸附等温线和吸附热力学行为.结果表明,材料对Pb2+的最大吸附容量为129.32 mg·g-1.吸附过程符合准二级动力学模型和Langmuir吸附等温式,表明材料对Pb2+的吸附是单分子层化学吸附;吸附热力学分析表明,吸附过程是一个自发的吸热过程,吸附驱动力主要来自吸附材料表面-NH2与Pb2+之间的配位作用.综上,所制备功能化磁性凹凸棒吸附材料对重金属离子具有良好的吸附性能,有望用于重金属离子废水的处理.  相似文献   

7.
A magnetic carbon composite, Fe3O4/C composite, was fabricated by one-step hydrothermal synthesis, modified by heat treatment under an inert atmosphere (N2), and then used as an adsorbent for ciprofloxacin (CIP) removal. Conditions for the modification were optimized according to the rate of CIP removal. The adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, vibrating-sample magnetometry, scanning electron microscopy, transmission electron microscopy, and N2 adsorption/desorption isotherm measurements. The results indicate that the modified adsorbent has substantial magnetism and has a large specific area, which favor CIP adsorption. The effects of solution pH, adsorbent dose, contact time, initial CIP concentration, ion strength, humic acid and solution temperature on CIP removal were also studied. Our results show that all of the above factors influence CIP removal. The Langmuir adsorption isotherm fits the adsorption process well, with the pseudo second-order model describing the adsorption kinetics accurately. The thermodynamic parameters indicate that adsorption is mainly physical adsorption. Recycling experiments revealed that the behavior of adsorbent is maintained after recycling for five times. Overall, the modified magnetic carbon composite is an efficient adsorbent for wastewater treatment.  相似文献   

8.
Novel amino (-NH2) functionalized mesoporous polyvinyl pyrrolidone (PVP)/SiO2 composite nanofiber membranes were fabricated by a one-step electrospinning method using poly (vinyl alcohol) and tetraethyl orthosilicate (TEOS) mixed with cationic surfactant, cetyltrimethyl ammonium bromide (CTAB) as the structure directing agent. Ureidopropyltriethoxysilane was used for functionalization of the internal pore surfaces. The membranes were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), element analyzer and N2 adsorption-desorption isotherms. The nanofiber diameters, average pore diameters and surface areas were 100-700 nm, 2.86 nm and 873.62 m2/g, respectively. These mesoporous membranes functionalized with -NH2 groups exhibited very high adsorptions properties based on the adsorption of Cr3++ from an aqueous solution. Equilibrium adsorption was achieved after approximately 20 min and more than 97% of chromium ions in the solution were removed. The membrane could be regenerated through acidification.  相似文献   

9.
以竞争吸附的一般模式为基础,修正了竞争吸附方程。研究了不同实验条件下修正竞争吸附方程的变化形式,为改进实验设计提供了理论依据。修正竞争吸附方程应用于描述pH对土壤吸附钴的影响,取得了满意的结果。  相似文献   

10.
TiO2/膨润土复合材料对Hg2+的吸附性能研究   总被引:1,自引:1,他引:0  
利用纳米TiO_2对膨润土进行复合改性,制备TiO_2/膨润土复合材料.采用电镜扫描、X-射线衍射表征改性前后膨润土的结构和形貌.通过室内模拟实验,以膨润土为对照,研究不同添加量、pH、吸附时间及初始Hg~(2+)浓度等条件下,TiO_2/膨润土复合材料对Hg~(2+)的吸附特性与性能,同时通过正交试验,探究TiO_2/膨润土复合材料吸附Hg~(2+)的最优条件.结果表明,改性后的膨润土颗粒明显变小,且颗粒疏松多空孔,层间距增大.相比于膨润土,TiO_2/膨润土复合材料吸附性能得到极大提高.TiO_2/膨润土复合材料对Hg~(2+)的吸附率均随着添加量、pH、吸附时间的增大而增大,添加量为1.5 g·L~(-1)、pH为7.0、吸附时间为120 min时,吸附率达98.0%以上.但TiO_2/膨润土复合材料对Hg~(2+)的吸附率随着初始Hg~(2+)浓度的增大而减小.通过4种动力学模型拟合发现,吸附过程符合假二级动力学方程,吸附以化学吸附为主.吸附等温线更符合Langmuir等温方程,属于典型的单分子层吸附,最大吸附量为20.66 mg·g-1.吸附Hg~(2+)的最优实验条件:添加量为2.0 g·L~(-1),pH为8.0,初始Hg~(2+)浓度为45 mg·L~(-1),吸附时间为16 h,此时吸附率99.9%,平衡浓度为0.034 mg·L~(-1).  相似文献   

11.
左旋氧氟沙星是一种新型污染物.单一的左旋氧氟沙星(LFV)和Ti O2无可见光响应,但二者共存下左旋氧氟沙星能发生显著的可见光降解.为此研究Ti O2用量、溶液p H以及左旋氧氟沙星浓度对Ti O2/Vis(可见光)降解左旋氧氟沙星的影响及机制.结果表明,左旋氧氟沙星能吸附在Ti O2表面,吸附服从准二级吸附动力学和Langmuir吸附等温线.吸附左旋氧氟沙星的Ti O2漫反射UV-Vis光谱进一步表明二者形成表面复合物.左旋氧氟沙星的Ti O2/Vis降解动力学符合LangmuirHinshelwood方程.合适的Ti O2浓度和中性p H有利于光解过程的进行.自由抑制实验、N2保护下左旋氧氟沙星的Ti O2/Vis降解实验揭示·O-2是该过程中的主要活性物种.同时,无氧左旋氧氟沙星-Ti O2悬浮液光照不同时间的UV-Vis光谱证明体系中存在电子向Ti O2导带的注入.依据实验结果提出吸附在Ti O2表面的左旋氧氟沙星与Ti O2形成表面复合物,在可见光照下发生电子迁移,从而引发左旋氧氟沙星降解.本研究表明利用污染与Ti O2形成表面复合物诱导其可见光降解可用来去除水中某些有机污染物.  相似文献   

12.
The mesoporous Cu/Mg/Fe layered double hydroxide(Cu/Mg/Fe-LDH) with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous solutions.The Cu/Mg/Fe-LDH was characterized by Fourier transform infrared spectrometry,X-ray diffraction crystallography,scanning electron microscopy,X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller.Effects of various physico-chemical parameters such as pH,adsorbent dosage,contact time and initial arsenate concentration on the adsorption of arsenate onto Cu/Mg/Fe-LDH were investigated.Results showed that it was efficient for the removal of arsenate,and the removal efficiency of arsenate increased with the increment of the adsorbent dosage,while the arsenate adsorption capacity decreased with increase of initial pH from 3 to 11.The adsorption isotherms can be well described by the Langmuir model with R 2 > 0.99.Its adsorption kinetics followed the pseudo second-order kinetic model.Coexisting ions such as HPO42-,CO32-,SO42and NO3could compete with arsenate for adsorption sites on the Cu/Mg/Fe-LDH.The adsorption of arsenate on the adsorbent can be mainly attributed to the ion exchange process.It was found that the synthesized Cu/Mg/Fe-LDH can reduce the arsenate concentration down to a final level of < 10 μg/L under the experimental conditions,and makes it a potential material for the decontamination of arsenate polluted water.  相似文献   

13.
酸碱改性生物炭对水中磺胺噻唑的吸附性能研究   总被引:6,自引:1,他引:5  
以马铃薯茎叶为原料,采用限氧裂解法制备生物炭,通过H2SO4和KOH处理制备酸、碱改性生物炭.应用比表面积法(BET)、扫描电镜(SEM)和红外光谱(FTIR)研究了改性前后3种生物炭的结构与性质,并通过单因素实验研究了吸附时间、温度、磺胺噻唑初始浓度、p H值等因素对原始及酸碱改性3种生物炭吸附磺胺噻唑效果的影响,初步探讨了吸附机制.结果表明,3种生物炭对磺胺噻唑的吸附行为符合准二级动力学方程;酸改性生物炭对磺胺噻唑的吸附等温线符合Temkin模型,原炭和碱改性生物炭的吸附等温曲线符合Freundlich模型.酸改性极大的提高了生物炭对磺胺噻唑的吸附能力,最大吸附量为7.69 mg·g-1,是原炭吸附量的2.4倍;溶液p H对3种生物炭吸附磺胺噻唑影响不明显.热力学研究表明,酸改性生物炭对磺胺噻唑的吸附为自发的吸热反应.FTIR分析表明,酸改性生物炭表面有更多含氧官能团,为磺胺噻唑的吸附提供了吸附点.氢键、范德华力及偶极距力作用对生物炭吸附磺胺噻唑起到主要作用.  相似文献   

14.
天然含水层介质对铀的吸附是地下水铀天然衰减的决定因素.然而,人们对天然含水层砂岩吸附铀行为的认识相当有限.因此,本文采用静态实验及数值模拟相结合的方法研究了地浸井场外围砂岩对铀的吸附行为,探究了天然砂岩对溶液中铀的吸附动力学和等温吸附特征,研究了铀初始浓度、pH、其他离子种类与浓度对铀吸附的影响.结果表明,准二级动力学方程与Freundlich等温吸附模型可以更好地表征砂岩对铀的吸附行为;随着溶液中铀初始浓度的增大,砂岩对水溶液中铀的吸附量增大,吸附率减小;在初始pH=3时,铀的吸附率达到最大,为77%;砂岩对溶液中铀的吸附率会随反应体系中Ca2+、Mg2+、SO42-、HCO3-等离子浓度的升高而下降,4种共存离子对该吸附过程抑制能力的顺序为:SO42- < Mg2+ < Ca2+ < HCO3-.这些研究结果可为地浸铀矿山地下水的修复提供理论支持.  相似文献   

15.
以暗棕壤为供试土壤,研究了不同溶液pH值、离子强度、接触时间、反应温度和初始铜离子(Cu~(2+))浓度条件下,胡敏素对Cu~(2+)的吸附作用;利用扫描电子显微镜(SEM)、X-射线能量色散谱(EDS)、傅立叶变换红外光谱(FTIR)和X-射线光电子能谱(XPS),对胡敏素/胡敏素-Cu~(2+)复合物的表面形貌、元素分布和官能团组成进行了分析;应用延展X-射线吸收精细结构谱(EXAFS),对吸附态Cu~(2+)的局域配位结构进行了表征.结果表明:胡敏素对Cu~(2+)的吸附量随pH值、接触时间、反应温度和Cu~(2+)浓度的增加而增加,但随离子强度的增加而下降;吸附动力学符合准二级动力学方程,而吸附等温线用Langmuir方程的拟合效果较好;吸附过程需要能量,是自发、吸热和自由度增加的缔合反应;吸附Cu~(2+)之后,胡敏素表面产生了团聚现象,表面羧基、羟基、吡啶氮和N—O基团参与了Cu~(2+)的吸附作用,同时吸附态Cu~(2+)是以内层配位形式与胡敏素表面的O/N和C原子结合.  相似文献   

16.
非活性黑根霉菌对废水中重金属离子的吸附   总被引:18,自引:1,他引:17  
屠娟  张利  赵力  俞耀庭 《环境科学》1995,16(1):12-15
为探讨发酵工业中废弃的菌丝体黑根霉菌(Rhizopusnigricans)对水中重金属离子的吸附特性,考察pH、浓度、共存离子等因素对吸附能力的影响,进行了实验室吸附试验,绘制出吸附等温线,并由Langmuir曲线和Freundlich曲线求出相应参数。对化学改性前后的黑根霉进行了吸附对比。初步分析了吸附机理。结果表明,黑根霉在pH=3—6.5范围内,对Pb2+、Cu2+、Mn2+、Cr(VI)几种主要重金属离子都有吸附作用,其中吸附Pb2+能力最高,饱和吸附量可达88mg/g。经化学改性的黑根霉可不同程度地提高吸附能力。用0.5mol/LHCI和NaoH可以洗脱和再生。  相似文献   

17.
铁锰复合氧化物吸附去除五价锑性能研究   总被引:11,自引:2,他引:9  
对比研究了铁锰复合氧化物(FMBO)、羟基氧化铁(FeOOH)和二氧化锰(MnO2)吸附去除五价锑(Sb(V))的性能.结果表明FMBO对Sb(V)具有很好的吸附性能,在pH=5.0的条件下,最大吸附容量达到1.05 mmol·g-1,略高于FeOOH (0.82 mmol·g-1)及远高于MnO2 (0.43 mmol·g-1);采用Freundlich模型可以很好地描述Sb(V)在FMBO的吸附行为(R2 = 0.98).就吸附动力学而言,假二级动力学可很好地描述Sb(V)在FMBO (R2 = 0.93)和MnO2表面的吸附过程(R2 = 0.96),而Sb(V)在FeOOH表面的吸附过程可用Elovich模型拟合 (R2 = 0.94).Sb(V)的吸附量随着pH值的升高而降低;磷酸盐显著抑制了Sb(V)的吸附,而硫酸盐和碳酸盐影响不大.提高体系离子强度可促进Sb(V)在FMBO表面的吸附,推断Sb(V)在FMBO表面形成内层络合物后被吸附去除.  相似文献   

18.
纳米磁性磷酸二氢钙对Cd的吸附、回收与再生   总被引:4,自引:3,他引:1  
以Ca(H2PO42、铁盐与亚铁盐为原料,采用共沉淀法制备成纳米磁性材料Ca(H2PO42@Fe3O4(NMCDP),研究其对Cd2+的吸附、回收与再生效果.透射电镜(TEM)、红外光谱(FTIR)、X射线衍射(XRD)显示,NMCDP粒径约60 nm,稳定性良好,饱和磁化强度为30.9 emu·g-1.吸附动力学表明,NMCDP对Cd2+的吸附1 h之内即可达到平衡,符合准二级动力学模型.吸附热力学表明,NMCDP对Cd2+的吸附符合Langmuir与Freundlich等温吸附模型,最大吸附量为142.50 mg·g-1.在pH值由2增加到3时,吸附量随溶液初始pH值的升高而增加,当pH值大于3后,逐渐保持稳定;溶液中共存离子Na+、Mg2+、Cu2+对材料吸附Cd2+均有一定的影响,影响程度Cu2+ > Mg2+ > Na+.采用0.01 mol·L-1 HCl与EDTA-Na2均可解吸出部分吸附的Cd2+,以EDTA-Na2解吸率较高,达到68%,从而实现NMCDP的再生.  相似文献   

19.
方文侃  李小娣  方菁  吴德意 《环境科学》2019,40(5):2295-2301
采用一步共沉淀法制备了磁铁矿纳米颗粒为核和水合氧化锆为壳的磁性氧化锆材料,研究了其除氟性能.结果表明,磁性氧化锆对氟的Langmuir最大吸附量为35. 46 mg·g~(-1),远高于磁铁矿、活性氧化铝和活性炭.磁性氧化锆对氟的吸附过程较快且吸附动力学数据符合准二级动力学模型,吸附过程为吸热反应.磁性氧化锆对氟的吸附量随pH升高而降低. Cl~-、NO_3~-和SO_4~(2-)的共存对磁性氧化锆除氟没有明显影响,而HCO_3~-和CO_3~(2-)明显抑制氟的吸附.磁性氧化锆吸附的氟可通过1mol·L~(-1)NaOH成功脱附,脱附率99. 5%~99. 6%.脱附后的磁性氧化锆经过再生处理可继续使用.磁性氧化锆对实际井水中的氟的去除效果低于纯水,但适当增加投加量仍可以达到饮用水标准对氟浓度的要求.磁性氧化锆制备简单、使用后可从水中磁分离从而可反复使用,因此是一种有较好应用前景的除氟材料.  相似文献   

20.
石墨烯基磁性复合材料吸附水中亚甲基蓝的研究   总被引:3,自引:2,他引:1  
常青  江国栋  胡梦璇  黄佳  唐和清 《环境科学》2014,35(5):1804-1809
建立了一种超声辅助共沉淀法制备磁性Fe3O4/氧化石墨烯(Fe3O4/GO)纳米粒子.透射电镜和磁滞回线研究表明,该复合物具有小的颗粒尺寸和超顺磁性.该磁性纳米材料可以吸附废水中的染料亚甲基蓝,实验研究了溶液pH值、吸附剂的用量、时间和温度对亚甲基蓝去除率的影响.结果表明,pH值在6~9范围内,Fe3O4/GO都能高效地吸附亚甲基蓝.反应过程在前25 min反应速率很快,到180 min内达到吸附平衡.该磁性纳米材料对亚甲基蓝的吸附符合Langmuir吸附等温模型和准二级动力学方程,吸附过程是一个自发和吸热过程.该吸附材料对亚甲基蓝吸附容量高,在313 K时Fe3O4/GO的饱和吸附量为196.5 mg·g-1.另外,可以方便地通过外部磁场分离回收吸附剂,利用过氧化氢可以再生重复使用,是一种优良的吸附染料废水的材料.  相似文献   

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