Capacity of Activated Carbon Derived from Peach Stones by K2CO3 in the Removal of Acid, Reactive, and Direct Dyes from Aqueous Solution

The present research deals with the production of activated carbon by chemical activation using peach stones and its adsorption behavior. The prepared activated carbon was used for the adsorption of three kinds of textile dyes, acid, reactive, and direct dyes, from aqueous solution. The results indicated that the overall adsorption process followed the pseudo-second-order kinetic model. The equilibrium data were found to be well represented by the Langmuir adsorption isotherm model. The calculated adsorption capacities for Reactive Orange 16, Acid Yellow 11, and Direct Red 23 onto activated carbon were 667, 539, and 427?mg?g?1 at 50°C, respectively. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were also calculated and indicated that the adsorption of dyes onto activated carbon was spontaneous and endothermic in nature.     

改性纳米二氧化钛对镍(Ⅱ)吸附行为的研究和分析应用

利用浸渍法对纳米TiO2进行表面改性,制备出改性纳米TiO2,并用扫描电镜(SEM)对其进行了表征。以火焰原子吸收光谱法(FAAS)探讨了改性纳米TiO2在静态吸附条件下对Ni(Ⅱ)的吸附性能,影响吸附和解脱的主要因素及Ni(Ⅱ)的吸附等温线,常见共存离子对Ni(Ⅱ)测定的影响,并做了再生实验。结果表明:在pH 8.0,振荡5 min,静置12 h条件下,0.100 0 g改性纳米TiO2能定量吸附Ni(Ⅱ);10 mL 4 mol/L硝酸作为解脱剂可使Ni(Ⅱ)定量解脱;改性纳米TiO2对Ni(Ⅱ)的吸附性能良好。该吸附剂已用于环境水样中Ni(Ⅱ)的测定。     

Cr(VI) Adsorption onto Hydrous Concrete Particles from Groundwater

Adsorption of Cr(VI) onto hydrous concrete particles in synthetic groundwater was investigated with batch equilibrium adsorption experiments. Results show marked adsorption under acidic conditions, and the amount of Cr(VI) adsorbed decreases with increasing solution pH and surface loading. A surface complex formation model was employed to describe the adsorption of Cr(VI) onto concrete particles. The adsorption-free energy of HCrO?4 and CrO2?4 species are ?6.16 and ?8.53 kcal∕mol, respectively. Results also indicate that specific chemical interaction is the major mechanism responsible for the adsorption process.     

粉煤灰处理含钼废水的效果及吸附机理研究

利用粉煤灰对模拟的含钼废水进行除钼吸附实验,分别研究了吸附过程中溶液pH值、吸附剂投加量对吸附效果的影响,并对吸附等温方程及动力学进行了探讨。结果表明,在吸附质钼初始浓度为10mg/L、pH=3.1条件下,粉煤灰对钼的吸附效果最好,除钼率为74.3%;对于50mL的含钼溶液,当吸附剂投加量为2.5g时除钼率达到最高值85.4%。粉煤灰对钼的吸附符合Langmuir吸附等温方程,以表面单分子层吸附为主;吸附过程符合二阶动力学模型,同时具有物理吸附和化学吸附的特征。     

粉煤灰负载铈吸附剂的制备研究

研制了一种新颖的铈负载粉煤灰吸附剂.研究了在各种制备条件下制得的吸附剂对氟离子的去除效果.实验结果表明,在pH为8～10,接触时间为16h,焙烧温度为400℃,铈离子浓度为0.2g/L,改性酸浓度为6mol/L时制得的稀土粉煤灰吸附剂,在处理氟离子水溶液时,该吸附剂除氟能力达到了90%以上.并且对比了原状粉煤灰、酸改性粉煤灰和稀土粉煤灰去除氟离子的吸附效率和最佳pH值.     

氧化石墨烯/壳聚糖复合微球的制备及其对铌的吸附性能

实验采用改进Hummers法合成了氧化石墨烯(GO),再用壳聚糖(CS)与GO制备了交联壳聚糖微球(GCCS)和GO质量分数分别为2%、5%、10%的氧化石墨烯/壳聚糖复合微球(GOCS),对其进行了表征,并研究了其对Nb的草酸配合物的吸附性能。结果表明,在1mmol/L的H_2C_2O_4溶液介质中,优化的吸附条件为GOCS中GO的质量分数为5%、pH=3。该吸附反应符合Langmuir等温吸附模型,为单层吸附,理论最大吸附量为38.46mg/g。动力学实验表明,该吸附反应符合准二级动力学模型。热力学实验表明,该吸附反应为自发反应、放热反应。采用5mL 1mol/L的HNO_3溶液进行洗脱实验,洗脱率为84.9%。3次吸附洗脱循环实验,吸附率和洗脱率并未出现明显下降,表明再生性能良好。     

Adsorption and desorption properties of D151 resin for Ce(Ⅲ)

The present research is aimed at the development of D151 resin as an adsorbent that it can be used in the adsorption of Ce(Ⅲ) ions.The adsorption and desorption behaviors of Ce(Ⅲ) on D151 resin have been investigated by chemistry analysis.The influence of operational conditions such as contact time,initial concentration of Ce(Ⅲ),initial pH of solution and temperature on the adsorption of Ce(Ⅲ) had also been examined.The results show that the optimal adsorption condition of D151 for Ce(Ⅲ) was achieved at pH=6.50 in HAc-NaAc medium.The maximum uptake capacity of Ce(Ⅲ) was 392 mg/g resin at 298 K.The adsorption of Ce(Ⅲ) followed both the Langmuir isotherm and Freundlich isotherm,and the correlation coefficients had been evaluated.Even kinetics on the adsorption of Ce(Ⅲ) had been studied.The adsorption rate constant k298 K valued was 1.3×10-5 s-1.The calculation data of thermodynamic parameters which ΔS0 value of 91.34 and ΔH0 value of 7.07 kJ/mol indicate the endothermic nature of the adsorption process.While,a decrease of Gibb’s free energy(ΔG0) with increasing temperature indicated the spontaneous nature of the adsorption process.Finally,Ce(Ⅲ) could be eluted by using 0.5 mol/L HCl solution and the elution percentage was as high as 100%.Adsorption mechanism was also proposed for the adsorption of Ce(Ⅲ) ions onto D151 resin using infrared spectroscopy technique.     

Adsorption of erbium(III) on D113-III resin from aqueous solutions: batch and column studies

The adsorption and desorption behaviors of Er(III) ion on D113-III resin were investigated. Batch adsorption studies were carried out with various Er(III) ion concentrations, pH, contact time and temperature, indicating that D113-III resin could adsorb Er(III) ion effectively from aqueous solution. The loading of Er(III) ion onto D113-III resin increased with increasing the initial concentration. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.45 to 6.75. In the batch system, the D113-III resin exhibited the highest Er(III) ion uptake as 250 mg/g at 298 K, at an initial pH value of 6.04, calculated from the Langmuir isotherm model. The adsorption kinetics was in agreement with Lagergren-first-order kinetics among the Lagergren-first-order model, pseudo-second-order model, liquid film diffusion model and intraparticle diffusion model. The adsorption data gave good fits with Langmuir isotherms. The thermodynamic parameters such as ΔG, which were all negative, indicated that the adsorption of Er(III) ion onto D113-III resin was spontaneous and the positive value of ΔH showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Er(III) ion could be eluted by using the 4.0 mol/L HCl solution. The characterization of both before and after adsorption of Er(III) ion on D113-III resin was undertaken with IR spectroscopic technique. Moreover, the surface characterization of D113-III resin was described by scanning electron micrographs (SEM).     

Adsorption Thermodynamics and Kinetics of Malachite Green onto Ca(OH)2-Treated Fly Ash

Fly ash, an industrial by-product abundant in India, was treated with alkali and tested as a low-cost adsorbent for the removal of malachite green from an aqueous solution in a batch adsorption procedure. Effects of stirring rate, temperature, pH, initial dye concentration, contact time, and adsorbent dose were investigated. The adsorption was found to be strongly dependent on pH of the medium and the adsorption capacity decreased with an increase in temperature. The Langmuir isotherm model showed a good fit to the equilibrium adsorption data at all temperatures. The mean free energy (E) estimated from the Dubinin-Radushkevich model indicated that the adsorption mechanism was chemical ion exchange. The kinetic data were found to follow the pseudo second-order kinetic model. The rate constant decreased with the increase in temperature indicating the exothermic nature of adsorption. Intraparticle diffusion was not the sole rate-controlling factor. The Arrhenius and Eyring equations were used to evaluate the activation parameters. The activation energy (Ea) was estimated to be 56.08??kJ?mol-1. Gibbs free energy (ΔG0) was spontaneous for all interactions, and the adsorption process exhibited exothermic enthalpy values. Results suggest that alkali-treated fly ash is a potential low-cost adsorbent for removal of malachite green from an aqueous solution.     

粉煤灰活性炭吸附含Cr废水试验研究

利用电厂粉煤灰可制备出具有较高吸附性能的粉煤灰活性炭.研究了不同pH值、投加量、时间、温度、溶液浓度、脱附方法条件下粉煤灰活性炭对Cr(Ⅵ)吸附性能的影响.结果表明,吸附反应为吸热过程;当粉煤灰活性炭掺入比为1∶250、pH值为2、25℃恒温振荡120 min时,粉煤灰活性炭最大吸附容量能达到4.67 mg/g;Cr饱和的粉煤灰活性炭,用0.05 mol/L浓度的NaOH脱附效果最佳,脱附率为129%.废弃印刷线路板湿式处理工艺中产生的废水,含Cr(Ⅵ)0.62 mg/L,在上述条件下,Cr(Ⅵ)去除率达95.16%;若在自然pH条件下,Cr(Ⅵ)的去除率能达到91.94%,均符合污水综合排放标准.粉煤灰活性炭用于含金属废水的处理有着广阔的应用前景.     

改性粉煤灰吸附稀土氨氮废水的机理研究

分别用氢氧化钠、硫酸和稀土镧对粉煤灰进行改性,然后用对比法研究了粉煤灰改性前后对稀土氨氮废水的吸附行为。结果表明,碱改性粉煤灰对稀土氨氮废水的吸附效果最佳。在室温下,pH为11.7,投加量5g,吸附达到平衡时,碱改性粉煤灰的吸附效率可以达到81.56%。碱改性粉煤灰吸附稀土氨氮废水的吸附过程符合Elovich吸附方程,属于良性吸附,吸附容量达到1.72mg/g。     

Adsorption and desorption properties of D151 resin for Ce(III)

The present research is aimed at the development of D151 resin as an adsorbent that it can be used in the adsorption of Ce(III) ions. The adsorption and desorption behaviors of Ce(III) on D151 resin have been investigated by chemistry analysis. The influence of operational conditions such as contact time, initial concentration of Ce(III), initial pH of solution and temperature on the adsorption of Ce(III) had also been examined. The results show that the optimal adsorption condition of D151 for Ce(III) was achieved at pH=6.50 in HAc-NaAc medium. The maximum uptake capacity of Ce(III) was 392 mg/g resin at 298 K. The adsorption of Ce(III) followed both the Langmuir isotherm and Freundlich isotherm, and the correlation coefficients had been evaluated. Even kinetics on the adsorption of Ce(III) had been studied. The adsorption rate constant k_{298 K} valued was 1.3×10^?5 s^?1. The calculation data of thermodynamic parameters which ΔS⁰ value of 91.34 and ΔH⁰ value of 7.07 kJ/mol indicate the endothermic nature of the adsorption process. While, a decrease of Gibb's free energy (ΔG⁰) with increasing temperature indicated the spontaneous nature of the adsorption process. Finally, Ce(III) could be eluted by using 0.5 mol/L HCl solution and the elution percentage was as high as 100%. Adsorption mechanism was also proposed for the adsorption of Ce(III) ions onto D151 resin using infrared spectroscopy technique.     

Evaluation of D113 cation exchange resin for the removal of Eu(III) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(III) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(III) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(III) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (?G) which were all negative, indicated that the adsorption of Eu(III) ions onto D113 resin was spontaneous and the positive value of enthalpy (?H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(III) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

碳点荧光猝灭法测定粉煤灰中痕量钴

在pH 6.80的B-R缓冲溶液中,基于钴离子对水溶性碳点(CDs)的荧光具有显著的猝灭作用,建立了一种测定钴离子的荧光光度法。在5 mL比色管中,依次加入0.5 mL 3.6×10^-4 mol/L荧光碳点溶液(以碳计)、1.0 mL pH 6.80的B-R缓冲溶液和适量的钴离子标准工作溶液后定容,室温下反应10 min,以350 nm为激发波长,440 nm为测定波长测定体系的相对荧光强度,结果表明,钴离子浓度在2×10^-6 ～7.6×10^-5mol/L范围内与CDs的相对荧光强度呈良好的线性关系,其线性回归方程为ΔF=1.008 7+0.031 25×10^-6 c(mol/L),相关系数r=0.998 5,方法检出限1.2×10^-7 mol/L。方法用于粉煤灰中痕量钴的测定,测定结果与国家标准方法GB/T 15922-2010相符,相对标准偏差(RSD,n=6)为0.9%～1.0%,加标回收率在98%～104%之间。     

吸附法脱除硫酸锰溶液中残余有机物

探讨粉煤灰、活性炭和膨润土等吸附剂对硫酸锰溶液中残余少量有机物的吸附效果,并以膨润土为吸附剂进行单因素试验,考察了膨润土用量、吸附时间、pH和温度对吸附效果的影响。结果表明,使用膨润土吸附剂,在溶液pH为7.0,25℃,吸附时间30min,膨润土用量10.0g的条件下,硫酸锰溶液的COD去除率可达32.4%;改性膨润土较未改性原土脱除溶液中有机物的效果更好,且酸化改性膨润土优于热化改性膨润土,COD去除率达到40.8%。     

Ion-exchange equilibria of Ni, Co, Mn and Mg with iminodiacetic acid chelating resin Amberlite IRC 748

A chelating ion-exchange resin, Amberlite IRC 748 which carries an iminodiacetate acid functional group has been investigated for its adsorption properties towards Ni, Co, Mn and Mg from aqueous solution. Experiments were conducted through batch adsorption by varying the resin volume at three different pH values. It was observed that the amount of metals adsorbed by the resin increased with increasing pH. The applicability of both the Langmuir and Freundlich isotherms were analyzed on the equilibrium data obtained. In all cases, the Langmuir isotherm shows an excellent fit to the experimental data while the Freundlich isotherm failed to predict the data at higher loadings. The resin exhibited high selectivity towards nickel (K = 58,000) and cobalt (K = 16,800), which can be easily separated from magnesium and manganese at pH 4 and 5. The obtained values of the equilibrium constant K (l/mol) matched the expected order of selectivity of this resin which is Ni > Co > Mn > Mg. The results also showed that the adsorption mechanisms of these metals onto the resin follow a combination of monolayer and multilayer adsorption.     

D113离子交换树脂对Mn(Ⅱ)的吸附性能

在常温条件下研究D113树脂吸附Mn(Ⅱ)的过程。结果表明,当溶液pH为6.5～7.0、吸附时间120min时,废水中Mn(Ⅱ)离子去除率可以达到99%,吸附容量为136.98mg/g。盐酸浓度为3～4mol/L时,一次解吸率均达100%。该树脂对Mn(Ⅱ)的吸附曲线符合Langmuir和Freundlich吸附等温线,吸附交换过程符合HO准二级动力学方程式。内扩散系数随溶液pH、溶液中Mn(Ⅱ)浓度的增大而增大。     

Adsorption Characteristics of Oxide Coated Buoyant Media (ρs<1.0) for Storm Water Treatment. II: Equilibria and Kinetic Models

Divalent metal species adsorption onto a manganese oxide coated polymeric medium (MOPM) was evaluated through batch adsorption experiments using a flow-through batch reactor. In this paper, Part II, the batch equilibrium and kinetic data examined in Part I are modeled using a triple layer surface complexation model and a potential driving second order kinetic model. Surface complexation modeling using FITEQL-TLM generated intrinsic surface acidity constants for the MOPM of log?K?a1int = 3.196 and log?K?a2int = ?5.802. The intrinsic surface reaction constants for Pb(II), Cu(II), and Zn(II) were log?K?Pbint = ?1.91, log?K?Cuint = ?2.53, and log?K?Znint = ?4.45, respectively. A potential driving second order kinetic model was developed to predict sorption of the divalent metal ions onto the MOPM. The general adsorption kinetics for MOPM can be described as a fast reaction occurring within 30 min and a slower reaction continuing from 5 to 15 h. Kinetic results can be interpreted using assumptions of the potential driving second order model that the dominant control forces are the chemical potential of the MOPM activated surface sites and chemical potential of sorbate in the solution.     

Study on the adsorption of lanthanum(III) from aqueous solution by bamboo charcoal

The adsorption behaviors of La(III) ion on bamboo charcoal were investigated with various chemical methods and IR spectrometry. Parameters studied include the effects of pH, average particle size, initial ion concentration, contact time and temperature by batch method. The results showed that bamboo charcoal could remove La(III) ions effectively from aqueous solution. The loading of La(III) ions was strongly dependent on pH of the medium and the optimal adsorption condition was in HNO₃-TEA medium with pH value of 7.20. In the batch system, the modified bamboo charcoal exhibited the highest La(III) ion uptake as 120 mg/g at 298 K, at an initial pH value of 7.20. The adsorption kinetics were tested with Lagergren-first-order model and pseudo-second-order model. The adsorption data were conformed to the Langmuir and Freundlich isotherms, and the correlation coefficients had been evaluated. Thermodynamic parameters such as free energy (ΔG), which were all negative, indicated that the adsorption of La(III) ion onto bamboo charcoal was spontaneous and the positive value of enthalpy (ΔH) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. The characterization of both before and after adsorption of La(III) ion on bamboo charcoal was undertaken using IR spectroscopic technique. The results revealed that bamboo charcoal was a good choice as a biosorbent for the recovery of lanthanum from aqueous solution.     

Adsorption of arsenate and arsenite from aqueous solutions by cerium-loaded cation exchange resin

The removal of arsenic from water and wastewater is obligatory.Resin is one of the most effective adsorbents for the removal of arsenic.In order to improve the adsorption capacity of resin,a new cerium-loaded cation exchange resin arsenic adsorbent was prepared by impregnating cerium into the cation exchange resin.Batch adsorption experiments under various conditions,such as time,temperature,pH and with coexisting ions were carried out to evaluate the adsorption characteristics of cerium-loaded resin in the removal of As(Ⅴ)and As(Ⅲ) from aqueous solutions.The results showed that the adsorption kinetics of As(Ⅴ)and As(Ⅲ)obeyed a pseudo second-order kinetic model and the adsorption rate constants were 0.3159 and 0.5215 g·mg-1 ·min-1 ,respectively.The adsorption of As(Ⅴ)followed the Freundlich adsorption isotherm model and the adsorption isotherm data for As(Ⅲ)fitted well to the Langmuir equation model.The adsorption capacities were 1.0278 mg/g for As(Ⅴ)and 2.5297 mg/g for As(Ⅲ).Both the adsorption of As(Ⅴ)and As(Ⅲ)were found to be pH sensitive and the optimum pH was found to be 5-6.Except for the phosphate ion,the coexisting anionics,such as nitrate,chlorate,sulphate and carbonate,showed no remarkable effect on As(Ⅴ)and As(Ⅲ)adsorption.The desorption and regeneration study showed that the adsorption capacity of Ce-loaded resin for As(Ⅴ)and As(Ⅲ)could be restored to 97.80%and 69.61%,respectively,using 0.5 mol/L sodium hydroxide solution.