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1.
用壳聚糖包埋磁流体,用戊二醛交联制成磁性壳聚糖微球,并用红外光谱表征其结构。用制备的磁性壳聚糖微球吸附Cr(Ⅵ)离子,考察了其对Cr(Ⅵ)离子的吸附性能;探讨了吸附时间、溶液pH值、吸附剂用量、温度、Cr(Ⅵ)起始浓度以及其他离子存在对Cr(Ⅵ)离子去除率的影响。实验结果表明,磁性壳聚糖微球吸附Cr(Ⅵ)离子的最佳条件为:吸附平衡时间40 min,最佳吸附pH值6左右,磁性壳聚糖微球用量10 mg,温度升高有利于提高磁性壳聚糖微球的吸附效率,Cr(Ⅵ)离子起始质量浓度为12μg/mL,无机盐的存在引起磁性壳聚糖微球的吸附性能降低。并且考察了吸附剂的再生性能,实验结果表明磁性壳聚糖微球具有良好的重复使用性。 相似文献
2.
水的氟污染是全世界普遍存在的问题,因此受到了人们的极大关注。我们研究重点是使用活性氧化铝及再生后的活性氧化铝脱除水中的氟离子。为了得到合适的吸附剂,我们将工业薄水铝石在573 K至1473 K范围内进行煅烧,并对其进行表征。从X射线衍射图中可以看出,当煅烧温度在773 K至1473 K之间时,样品转化为γ-氧化铝(活性氧化铝)。且BET数据显示,当煅烧温度在773K至1473K之间时,样品的比表面积逐渐降低。在本实验中,我们选用773K、873K、973 K煅烧的活性氧化铝作为除氟吸附剂,同时选用动态吸附法移除水中的氟离子。突破曲线表明吸附容量随着煅烧温度的增加而降低。为了研究氟离子的初始浓度对吸附容量的影响,我们选用15 mg·L~(-1)、20 mg·L~(-1)、25 mg·L~(-1)的氟离子溶液作为初始溶液,且吸附剂的吸附容量随着初始浓度的增加而增加。当活性氧化铝吸附氟离子达到饱和后,用pH值为13.0、13.3和13.5的氢氧化钠溶液对其再生,并用0.1 mol·L~(-1)的盐酸溶液对其进行活化以提高吸附剂的吸附能力。通过比较五次再生过程中的解吸率和铝溶解率,可以看出pH值为13.0的氢氧化钠溶液最适合作解吸剂。通过分析吸附剂的氮气吸-脱附等温线,发现再生后的吸附剂的氮气吸脱附等温线的形状并没有发生很大的变化,说明再生过程中吸附剂的孔结构并没有被破坏。五次再生过程中吸附剂的比表面积和等电点的变化是影响吸附容量很重要的两个因素,发现吸附剂再生后其比表面积和等电点均增加。为检测再生吸附剂的吸附效果,每次再生后都需要进行一次吸附实验。突破曲线表明,和初始活性氧化铝相比,再生后达到饱和所用的时间更短,吸附量越大。为了探究吸附机理,我们用红外光谱表征吸附剂中的羟基,发现再生过程中吸附剂中Al―O―H含量的变化是影响活性氧化铝对氟离子吸附量的关键因素。 相似文献
3.
《应用化学》2019,(3)
采用溶胶-凝胶法、一锅反应法制备了负载纳米TiO_2和Fe_3O_4的凹凸棒黏土(TiO_2-Fe_3O_4-ATP)吸附剂,并进行了模拟废水中Cr(Ⅵ)的吸附及脱附性能的研究。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和EDS等分析方法对ATP负载纳米TiO_2-Fe_3O_4前后结构进行了表征,考察了物料配比及吸附时间、pH值、温度、投加量和初始质量浓度对Cr(Ⅵ)吸附率的影响。结果表明,吸附剂在Ti元素含量与负载总量的摩尔比为3∶4时吸附效果最佳。当吸附剂质量为0. 6 g,Cr(Ⅵ)离子初始质量浓度小于0. 8 mg/L时,pH=6,温度20℃,吸附剂对Cr(Ⅵ)的吸附率为79. 8%。TiO_2-Fe_3O_4-ATP吸附剂对Cr(Ⅵ)离子吸附满足Freundlich模型。在20~40℃条件下,吸附过程ΔG 0、ΔS=-43. 55 J/(mol·K)、ΔH=-14. 36 k J/mol,表明该吸附是个自发、熵减、放热的过程。吸附过程符合准二级动力学模型,吸附速率控制步骤以表面化学反应为主。TiO_2-Fe_3O_4-ATP吸附剂在循环使用4次后,吸附率仍能达到65%以上。 相似文献
4.
焙烧层状氢氧化镁铝对水中氟离子的吸附性能 总被引:1,自引:0,他引:1
研究了焙烧层状氢氧化镁铝(CLDH)对水中氟离子的吸附性能,考察了焙烧温度、吸附时间、吸附剂用量、溶液pH值等条件对吸附的影响.发现在较宽的pH(5.5~9.5)值范围内,CLDH对水中氟离子具有良好的吸附能力,室温下0.2gCLDH可将50mL浓度为15mg/L氟离子溶液处理为符合含氟标准的饮用水.吸附平衡符合Langmuir方程,在60min内达到饱和吸附,室温下饱和吸附量为22.64 mg/g.吸附饱和后的CLDH焙烧再生,循环使用5次后饱和吸附量为10.37 mg/g. 相似文献
5.
壳聚糖经双氧水降解得到低分子量壳聚糖,用水杨醛对低分子量壳聚糖进行化学改性得到其相应的衍生物.分别研究了壳聚糖和水杨醛改性的低分子量壳聚糖对锆(Ⅳ)离子的吸附,考察了锆(Ⅳ)离子起始浓度、溶液pH值、吸附时间以及温度对这两种吸附剂吸附锆(Ⅳ)离子性能的影响,得出了最佳吸附条件.用红外对最佳条件下的吸附产物进行了表征.结果表明,壳聚糖吸附锆离子的最佳条件为:锆(Ⅳ)离子的起始浓度为6.5×10-4g/mL,振摇时间为6.5h,pH值为5~6;水杨醛改性的低分子量壳聚糖吸附锆离子的最佳条件为:锆离子的起始浓度为4.7×10-4g/mL,振摇时间为5h,pH值为5~6.这两种吸附剂对锆(Ⅳ)离子的吸附受温度影响均不大,吸附行为均满足Langmuir等温式.红外光谱分析表明,锆(Ⅳ)离子与这两种吸附剂均发生了配位作用. 相似文献
6.
以贻贝壳为绿色钙源,采用化学沉淀法制备吸附剂碳羟基磷灰石(CHAP),利用傅里叶红外光谱、扫描电镜、X射线衍射等测试技术对其形貌、结构和性质进行了表征;考察了CHAP对水中刚果红的吸附去除特性。结果表明:刚果红溶液的初始浓度为50.00 mg·L~(-1),pH为4.0,加入10.0 g·L~(-1)吸附剂,吸附温度在30℃的条件下吸附60 min,脱色率达99.08%,饱和吸附量为4.95 mg·g~(-1)。CHAP对水中刚果红的吸附动力学过程可以较好地采用准二级动力学模型描述。CHAP对刚果红的吸附平衡数据采用Langmuir和Freundlich等温吸附模型描述,Langmuir吸附等温式更适用于描述此吸附过程。热力学研究表明,CHAP对刚果红吸附为物理吸附,吸附过程存在热驱动。碳羟基磷灰石去除水中刚果红的机制是路易斯酸碱反应,吸附作用力为静电作用力、范德华力。热再生后的CHAP经过6个循环后,仍有96.71%的脱色率,表明CHAP具有良好的吸附性能,可以循环使用。 相似文献
7.
采用溶胶-凝胶法、一锅反应法制备了负载纳米TiO2和Fe3O4的凹凸棒黏土(TiO2-Fe3O4-ATP)吸附剂,并进行了模拟废水中Cr(Ⅵ)的吸附及脱附性能的研究。 通过扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和EDS等分析方法对ATP负载纳米TiO2-Fe3O4前后结构进行了表征,考察了物料配比及吸附时间、pH值、温度、投加量和初始质量浓度对Cr(Ⅵ)吸附率的影响。 结果表明,吸附剂在Ti元素含量与负载总量的摩尔比为3:4时吸附效果最佳。 当吸附剂质量为0.6 g,Cr(Ⅵ)离子初始质量浓度小于0.8 mg/L时,pH=6,温度20 ℃,吸附剂对Cr(Ⅵ)的吸附率为79.8%。 TiO2-Fe3O4-ATP吸附剂对Cr(Ⅵ)离子吸附满足Freundlich模型。 在20~40 ℃ 条件下,吸附过程ΔG<0、ΔS=-43.55 J/(mol·K)、ΔH=-14.36 kJ/mol,表明该吸附是个自发、熵减、放热的过程。 吸附过程符合准二级动力学模型,吸附速率控制步骤以表面化学反应为主。 TiO2-Fe3O4-ATP吸附剂在循环使用4次后,吸附率仍能达到65%以上。 相似文献
8.
《化学研究与应用》2017,(3)
为了提高吸附剂对水中孔雀石绿(MG)的去除效果,对埃洛石纳米管改性,制备了氨基功能化的埃洛石纳米管。将该材料用于水中MG的吸附,研究了溶液pH值、温度、吸附时间等因素对MG去除率的影响,考察了吸附机理、吸附选择性和吸附剂的循环使用性能。结果表明,在pH为4~10范围内材料对MG有较好的吸附性能,吸附量随温度的增加而增大;在最佳条件下,材料可去除水中浓度低至0.01 mg·L~(-1)的MG,最大吸附量高达48.40 mg·g~(-1),比改性前提高了101.73%;吸附过程主要是静电吸附,可通过溶液pH的改变调控吸附选择性,吸附剂可再生重复使用。将该方法用于5种实际水样中MG的吸附,去除率在97.14~99.04%之间。 相似文献
9.
本文以二氰二胺和硝酸镍为原料通过煅烧法在900℃合成了镍/碳纳米管(Ni-CNT)的复合材料,采用X射线粉末衍射(XRD),扫描电镜(SEM),透射电镜(TEM),傅里叶变换红外光谱(FTIR)等手段对产物进行了表征,并对其磁性进行了测量。探讨了不同条件下(吸附时间、吸附剂量、pH)产物对刚果红溶液吸附性能的影响。结果表明,当吸附时间达到20 min、吸附剂用量达到1.0 g·L~(-1)且pH值在8时产物对刚果红的吸附率最高,达到97.8%。循环实验表明其五次吸附后依然保持良好的吸附率,且在磁场作用下,吸附剂易与溶液分离。 相似文献
10.
采用溶胶-凝胶法制备了硅胶G基纳米钛酸锶钡,并且用X射线衍射(XRD)、扫描电镜(SEM)和傅立叶变换红外光谱(FTIR)进行了表征.系统地研究了该物质对水中铅的吸附性能.提出了硅胶G负载纳米钛酸锶钡分离富集,FAAS法测定水中痕量铅的新方法.结果表明,纳米钛酸锶钡能够负载于硅胶G表面,制成蚕茧状颗粒吸附材料.在pH值为4~6时,该吸附剂对水中的铅离子具有很强的吸附能力,静态吸附容量达到86.28m/g.吸附在硅胶G负载纳米钛酸锶钡上的铅离子可用1mol/L的硝酸完全洗脱下来,经硅胶G负载纳米钛酸锶钡富集10倍后,方法检出限为7.4μg/L.用于河水和自来水中痕量铅的测定,结果满意. 相似文献
11.
Ashraf Ali Sarah Alharthi Bashir Ahmad Alia Naz Idrees Khan Fazal Mabood 《Molecules (Basel, Switzerland)》2021,26(22)
The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater. 相似文献
12.
Batch adsorption experiments were carried out for the removal of methylene blue (MB) from aqueous solution using attapulgite as adsorbent. The effects of various parameters such as temperature, contact time, the pH value, and attapulgite dosage on the adsorption performance were investigated. The standard curve and regression equation were established by spectrophotometry. The adsorption experimental results showed that the adsorption equilibrium data were well in accord with Langmuir adsorptive model. The optimal result was acquired under the experimental condition of attapulgite dosage 0.18g, MB concentration 50.0mg/L, pH 10, and adsorption time 20min at room temperature. 相似文献
13.
嗜铅菌对水中重金属Pb~(2+)的吸附研究 总被引:3,自引:0,他引:3
研究了实验室提供的嗜铅菌对水中铅离子吸附的条件和机理.讨论了吸附时间、pH、铅离子的质量浓度和菌的质量浓度对吸附的影响.结果表明,在pH=7.0、铅离子初始质量浓度为25mg/L、离心湿菌的质量浓度为1.06g/L、吸附时间为60min时,铅离子的吸附率达96.88%;实验条件下超标25倍的含Pb~(2+)废水,可迭排放标准;Pb~(2+)的最大吸附量为150mg/g.数学模型Langmuir和Freundlich方程均能很好地描述嗜铅菌对Pb~(2+)的吸附过程.对Pb~(2+)吸附前后的红外光谱表征表明,嗜铅菌表面多糖、蛋白质的羟基峰和羰基峰均有不同程度的紫移,羟基峰、糖苷峰等峰宽略增,说明菌体吸附,主要是表面基团的作用所致.用原子力显微镜对吸附前后的嗜铅菌检测可见,吸附后菌体的弹性变小、粘性变大、部分茵体有一定的收缩,说明以表面吸附为主的吸附过程,对菌细胞的聚合度有影响,菌体内部对铅也有一定的生物积累. 相似文献
14.
A. Vijaya Bhaskar Reddy Rehan Rafiq Aqeel Ahmad Abdulhalim Shah Maulud Muhammad Moniruzzaman 《Molecules (Basel, Switzerland)》2022,27(22)
In the current study, we have synthesized an imidazolium based cross-linked polymer, namely, 1-vinyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide (poly[veim][Tf2N]-TRIM) using trimethylolpropane trimethacrylate as cross linker, and demonstrated its efficiency for the removal of two extensively used ionic dyes—methylene blue and orange-II—from aqueous systems. The detailed characterization of the synthesized poly[veim][Tf2N]-TRIM was performed with the help of 1H NMR, TGA, FT-IR and FE-SEM analysis. The concentration of dyes in aqueous samples before and after the adsorption process was measured using an UV-vis spectrophotometer. The process parameters were optimised, and highest adsorption was obtained at a solution pH of 7.0, adsorbent dosage of 0.75 g/L, contact time of 7 h and dye concentrations of 100 mg/L and 5.0 mg/L for methylene blue and orange-II, respectively. The adsorption kinetics for orange-II and methylene blue were well described by pseudo-first-order and pseudo–second-order models, respectively. Meanwhile, the process of adsorption was best depicted by Langmuir isotherms for both the dyes. The highest monolayer adsorption capacities for methylene blue and orange-II were found to be 1212 mg/g and 126 mg/g, respectively. Overall, the synthesized cross-linked poly[veim][Tf2N]-TRIM effectively removed the selected ionic dyes from aqueous samples and provided >90% of adsorption efficiency after four cycles of adsorption. A possible adsorption mechanism between the synthesised polymeric adsorbent and proposed dyes is presented. It is further suggested that the proposed ionic liquid polymer adsorbent could effectively remove other ionic dyes and pollutants from contaminated aqueous systems. 相似文献
15.
Adane Woldemedhin Kalsido Beteley Tekola Meshesha Beshah M. Behailu Esayas Alemayehu 《Molecules (Basel, Switzerland)》2021,26(23)
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. 相似文献
16.
Ganesh Jethave Rahul Rathod Jagdish Pawar 《Journal of Dispersion Science and Technology》2019,40(4):563-573
This study evaluated the feasibility of Rhodamine-B dye (Rh B) removal from aqueous solution, using Lead-Iron Oxide nanoparticles Loaded Activated Carbon (FePbO@AC). The parameters like pH, contact time, adsorbent/adsorbate dosage and temperature on adsorption was studied. Optimized conditions are pH of 7.0, 25?min contact time, 50?ppm of dye concentration and 200?mg of adsorbent concentration. The kinetics of adsorption was calculated using pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The calculations revealed that the pseudo-second-order kinetic equation best-fit the adsorption data. The Langmuir isotherm model best fit the equilibrium data. The maximum sorption capacity (Qmax) for dye is 1000?mg Rh B/g FePbO@AC. Change in entropy (ΔS), Gibb’s free energy change (ΔG), and enthalpy (ΔH) were calculated for the adsorption of Rh B dye. 相似文献
17.
《Arabian Journal of Chemistry》2020,13(6):5669-5678
Chitosan/MOF composite porous monolith used in water remediation as adsorbent can realize high-efficient removal of pollutant in water and facile recycling from water. However, dissolution of chitosan (without crosslinking) in acidic aqueous solution will cause breakage of composite monolith. Herein, we report a chitosan/UiO-66 monolith prepared by ice-templating method. Specially, a pre-crosslinking treatment (by glutaraldehyde) is employed before the monolith formation, which obviously boosts its stability in aqueous solution. The composite monolith is evaluated by SEM, N2 adsorption, XRD, and batch adsorption tests for Congo Red (CR). The results show that the composite monolith possesses a typical ice-templating structure with hierarchical (mirco- / meso- and macro-) pores. UiO-66 particles are embedded on the surface of chitosan matrix, and the crystal structure of UiO-66 is not changed obviously by the crosslinking and freezing process. The composite monolith exhibits high adsorption efficiency (90% of CR was removed from its aqueous solution in 60 min) and the maximum adsorption capacity of 246.21 mg/g (derived from Langmuir model) can be reached. After adsorption, the monolith is collected by a facile procedure and recovered using ethanol for evaluating its reusability. After 4 cycles, the CR removal efficiency of the composite monolith still remains ~90% of the initial efficiency. This work demonstrates that the simple crosslinking procedure before monolith formation can ensure the intact shape of the chitosan/MOF monolith during adsorption. 相似文献
18.
Mohammad Ali Karimi Hassan Masrouri Hassan Karami Saeed Andishgar Mehrnaz Alsadat Mirbagheri Tayebe Pourshamsi 《中国化学会会志》2019,66(10):1327-1335
A magnetic metal‐organic framework (MOF) nanocomposite was successfully prepared by a new and green strategy through reasonable design. Magnetic MOF of Fe3O4‐NHSO3H@HKUST‐1 nanocomposite use for removal of lead ions as an environmental pollutant. The experimental results indicated that the nano adsorbent of Fe3O4‐NHSO3H@HKUST‐1 can removed lead ions under optimum operational conditions. The dosage of the nanocomposite, pH of the sample solution, and contact time were obtained to be 10 mg, 7.0, and 90 min, respectively, while the initial concentration of Pb(II) ions of 400 mg/L was used. A kinetic study indicated that a pseudo‐second‐order model agreed well with the experimental data. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The maximum adsorption capacity of the adsorbent for the removal of lead under the optimum operational conditions of pH 7.0 and temperature 25°C was found to be 384.6 mg/g. The thermodynamic parameters indicate that the adsorption of lead is spontaneous and endothermic. The magnetic MOF nanocomposite could be recovered easily and reused many times without significant loss of its nano‐adsorbent activity. The proposed method is simple, eco‐friendly, low cost, and efficient in the removal of lead ions from aqueous solutions. 相似文献
19.
In this study, a novel hydrogel composite, poly[2-(dimethylamino) ethyl methacrylate]/pumice (PDMAEMA/Pmc) was designed and its sorption behavior for humic acid (HA) was produced by using batch adsorption techniques. FTIR results showed that pumice was well incorporated with the PDMAEMA matrix. A scanning electron microscopy (SEM) was used in order to determine the morphology of composite hydrogel. In the batch experiments, the adsorption capacity was evaluated depending on different variables such as ionic strength; initial HA concentration; pH and adsorbent dosage. The adsorption capacity was found to be 86.27 mg/g under the optimized conditions. The results revealed that HA adsorption onto PDMAEMA/Pmc was well expressed by the Freundlich isotherm model and the adsorption process was followed by the pseudo second order kinetic model. The reusability tests also indicated that novel PDMAEMA/Pmc adsorbent was an efficient and cost-effective adsorbent for removal of HA. 相似文献
20.
磷酸铝吸附除水中氟的研究 总被引:7,自引:0,他引:7
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。 相似文献