Biosorption of cadmium(II) and copper(II) ions from aqueous solution by core of Artocarpus odoratissimus

Purpose

This research is on the evaluation of biosorption capability of the core of Artocarpus odoratissimus (Tarap), grown in Brunei Darussalam, towards Cd(II) and Cu(II) ions present in synthetic solutions, and to characterize the surface of Tarap particles.

Methods

Thermogravimetric analysis and surface titrations were conducted to characterize the surface of dried Tarap core particles. Atomic absorption spectroscopic measurements were conducted to determine the extent of removal of Cd(II) and Cu(II) under different experimental conditions.

Results

Mass reductions associated with many exothermic reaction peaks were observed beyond 200°C up to 650°C indicating the combustion of organic matter in Tarap. Dried particles of core of Tarap bear a negative surface charge promoting strong interaction towards positively charged ions, such as Cu(II) and Cd(II). Biosorption of the two metal ions on Tarap, which is relatively high beyond pH?=?4, occurs within a short period of exposure time. The extent of biosorption is enhanced by acid treatment of the biosorbent, and further it does not significantly depend on the presence of nonreacting ions up to an ionic strength of 2.0?M.

Conclusion

Strong attraction between each metal ion and the biosorbent is attributed to the negative surface charge on the biosorbent within a broad pH range. Acid treatment of the biosorbent improves sorption characteristics, suggesting that ion exchange plays an important role in the metal ion??biosorbent interaction process.     

Batch and continuous adsorption of Cu(II) and Zn(II) ions from aqueous solution on bi-functionalized sugarcane-based biosorbent

Environmental Science and Pollution Research - A new one-pot synthesis method optimized by a 23 experimental design was developed to prepare a biosorbent, sugarcane bagasse cellulose succinate...     

改性松针对水体中铅(II)的吸附

探讨了改性松针(GXLsp)作为吸附剂对水体中铅离子的吸附性能,考察了吸附时间、溶液pH值、吸附剂用量、盐离子浓度、Pb(II)初始浓度及温度对改性松针吸附Pb(II)的影响。利用Langmuir和Freundlich等温线模型对实验数据进行非线性拟合分析,结果表明,Freundlich等温线模型能很好地描述松针对Pb(II)的吸附过程。热力学参数表明吸附是一个自发的吸热过程。改性松针对铅的吸附行为符合拟二级动力学方程,表明吸附过程是以化学吸附为主。在293K时松针对Pb(II)的饱和吸附量为318.3 mg/g,因此,GXLsp可作为一种高效低值生物质吸附剂以去除水体中重金属Pb(II)的污染。     

改性纤维素吸附剂的合成及其对铜离子的吸附

建立了一种简单方便的纤维素改性的固相合成方法。采用普遍廉价的滤纸作为原料,用固相合成法将预处理后的滤纸纤维经琥珀酸酐进行酯化改性,制备成新型的纤维素吸附剂,通过质量增比、扫描电镜、傅里叶红外光谱仪和X射线衍射仪对制备的吸附剂进行了分析表征,并且探究了离子初始浓度、溶液pH和吸附时间对改性纤维素吸附铜离子的影响。结果表明,在室温下初始离子浓度为1 000 mg/L,离子溶液体积为50 mL,加入0.1 g纤维改性剂,pH 为 4.0~5.0,吸附平衡时间为50 min时,滤纸纤维改性后最大吸附铜离子质量可达470 mg/g,铜离子去除率达到94%。     

Fabrication of novel bio-adsorbent and its application for the removal of Cu(II) from aqueous solution

Environmental Science and Pollution Research - As eco-friendly adsorption material, hydroxyapatite (Ca5(PO4)3OH, HA) has been extensively applied to the removal of heavy metal ions. However,...     

改性沸石对Cd(Ⅱ)的吸附平衡及动力学

采用等温吸附法比较了氢氧化钠、氯化钠、硝酸铵、硫酸、磷酸、混合盐和高温改性沸石对含镉废水的吸附效果,并采用Langmuir、Freundlich等温线方程及Lagrange假一级动力学方程、假二级动力学方程、粒内扩散方程对实验数据进行了拟合。结果表明,镉浓度大于10 mg/L时,NaOH改性沸石吸附效果最好,吸附率在99.2%以上;沸石对镉的吸附符合Langmuir方程,属单分子层吸附,最大吸附量Qm=6.456 mg/g;改性沸石对Cd2+的吸附动力学符合假二级动力学方程,以化学吸附为主,有多个控速步骤。     

Electrochemical and FTIR studies of the mutual influence of lead(II) or iron(III) and phenol on their adsorption from aqueous acid solution by modified activated carbons

Cyclic voltammetry and spectral FTIR studies of the influence of activated carbon surface modification on the co-adsorption of metal cation (lead or iron) and phenol from aqueous acidic solution were carried out. The diversity in surface chemical structure was achieved by applying different procedures of inorganic matter removal and by modifying the carbon samples in various ways: heating under vacuum, aminoxidation in an ammonia-oxygen atmosphere, oxidation with concentrated nitric acid. The quantities of adsorbed metal ions (Pb(2+) or Fe(3+)) and phenol from solutions containing cation or phenol separately or in a mixture were determined. The adsorption capacity from acidic aqueous acidic solution depends on the chemical properties of the activated carbon surface (e.g., decrease in phenol adsorption with relative lower basicity of the adsorbent). The electrochemical parameters of electrodes made from the carbon samples were estimated, and some possible electrochemical reactions were determined from voltammograms recorded in acid electrolyte solution containing adsorbed species (separately or as a mixture). Relationships were found between metal ion adsorption and electrochemical behavior of Pb(2+)/Pb(4+) and Fe(3+)/Fe(2+) couples on the one hand, and the presence of phenol in the solutions tested and the influence of surface chemistry of the carbon electrodes on electrochemical processes on the other. The changes in adsorption capacity with respect to the adsorbates used and the changes in FTIR spectra of the carbons as a result of adsorption and/or coupling phenol molecules are discussed.     

Removal of Pb(II) ions from aqueous solution and industrial effluent using natural biosorbents

Purpose

The purpose of the research is to investigate the applicability of the low-cost natural biosorbents for the removal of Pb(II) ions from aqueous solution and effluent from battery industry.

Methods

Six different biosorbents namely rice straw, rice bran, rice husk, coconut shell, neem leaves, and hyacinth roots have been used for the removal of Pb(II) ions from aqueous solution in batch process. All the biosorbents were collected from local area near Kolkata, West Bengal, India. The removal efficiency was determined in batch experiments for each biosorbent.

Results

The biosorbents were characterized by SEM, FTIR, surface area, and point of zero charge. The sorption kinetic data was best described by pseudo-second-order model for all the biosorbents except rice husk which followed intraparticle diffusion model. Pb(II) ions adsorption process for rice straw, rice bran, and hyacinth roots were governed predominately by film diffusion, but in the case of rice husk, it was intraparticle diffusion. Film diffusion and intraparticle diffusion were equally responsible for the biosorption process onto coconut shell and neem leaves. The values of mass transfer coefficient indicated that the velocity of the adsorbate transport from the bulk to the solid phase was quite fast for all cases. Maximum monolayer sorption capacities onto the six natural sorbents studied were estimated from the Langmuir sorption model and compared with other natural sorbents used by other researchers. The Elovich model, the calculated values of effective diffusivity, and the sorption energy calculated by using the Dubinin?CRadushkevich isotherm were indicated that the sorption process was chemical in nature. The thermodynamic studies indicated that the adsorption processes were endothermic. FTIR studies were carried out to understand the type of functional groups responsible for Pb(II) ions binding process. Regeneration of biosorbents were carried out by desorption studies using HNO₃. Battery industry effluents were used for the application study to investigate applicability of the biosorbents.

Conclusion

The biosorbents can be utilized as low-cost sorbents for the removal of Pb(II) ions from wastewater.     

改性陶粒对水中内分泌干扰物的吸附去除

用CTMAB(十六烷三甲基溴化铵)对陶粒进行改性.实验研究了陶粒改性前后对5种内分泌干扰物EDCs(美托洛尔MTP、磺胺甲噁唑SMZ、卡马西平CBZ、对氯苯氧异丁酸CA、17α-乙炔基雌二醇EE2)的吸附特性.结果表明,CTMAB改性处理对陶粒的孔结构和表面性质都有影响,有效吸附的孔径所占比例和陶粒表面极性升高;室温条件下,EDCs初始浓度和吸附剂浓度均为1 mg/L时,实验用改性陶粒和陶粒达到吸附平衡的时间基本相同,均为5 min左右;改性陶粒能提高大部分EDCs的吸附量,5种内分泌干扰物混合物一起吸附时存在竞争,其中SMZ和MTP竞争力强,CA最弱;吸附机理包括表面物理吸附和分配作用.实验研究拟为改性陶粒应用于水中痕量污染物的处理提供理论依据,支撑保障饮用水处理达标的目的.     

改性黄麻制备及其对铜离子的吸附

从地表水突发污染应急处置实际需求的角度,考虑纤维材料的现场实用性,研究了均苯四甲酸二酐改性黄麻的制备过程及对重金属铜离子的吸附性能,吸附等温线、吸附动力学和吸附热力学。通过正交实验对改性条件进行了优化,结果表明,反应物(黄麻与酸酐)配比和反应温度对改性黄麻的吸附量有十分显著的影响;在室温,pH为5~7的条件下,改性黄麻对铜离子的吸附容量为43.56 mg/g,比原态黄麻提高了7倍多;改性黄麻对铜离子的吸附符合Langmuir模型,为单分子层吸附;吸附过程是符合假二级动力模型的自发吸热反应。     

Removal and recovery of copper and nickel ions from aqueous solution by poly(methacrylamide-co-acrylic acid)/montmorillonite nanocomposites

Nanocomposite hydrogels based on poly(methacrylamide-co-acrylic acid) and nano-sized montmorillonite were prepared by aqueous dispersion and in situ radical polymerization. Optimum sorption conditions were determined as a function of montmorillonite content, contact time, pH, and temperature. The equilibrium data of Cu²⁺ and Ni²⁺ conformed to the Freundlich and Langmuir isotherms in terms of relatively high regression values. The maximum monolayer adsorption capacity of the nanocomposite hydrogel (with 3 wt% montmorillonite content), as obtained from the Langmuir adsorption isotherm, was found to be 49.26 and 46.94 mg g^?1 for Cu²⁺ and Ni²⁺, respectively, at contact time?=?60 min, pH?=?6.8, adsorbent dose?=?100 mg/ml, and temperature?=?318 K. Kinetic studies of single system indicated that the pseudo-second order is the best fit with a high correlation coefficient (R ²?=?0.97–0.99). The result of five times sequential adsorption–desorption cycle shows a good degree of desorption and a high adsorption efficiency.     

多胺基水凝胶的合成及其对铜离子的吸附

以聚乙烯亚胺和2-丙烯酸羟乙酯为共聚单体,采用60Co-γ射线辐照法,制备了新型多胺基水凝胶p（PEI/HEA）,并对其进行了红外光谱和X射线电子能谱表征。通过静态吸附实验研究了其对水溶液中Cu（Ⅱ）的吸附性能,结果表明,随pH值的升高,水凝胶的吸附量逐渐增加,在pH=5.5时达到最大;p（PEI/HEA）对Cu（Ⅱ）的吸附动力学过程遵循准二级动力学模型,吸附等温过程符合Langmuir单分子层吸附,最大吸附量为28.98 mg·g-1。     

多基团秸秆纤维对水体中铜/磺胺甲恶唑复合污染物的定量吸附性能

以秸秆纤维为研究对象,通过醚化和接枝化修饰方法赋予其纤维结构的季胺基(-N⁺)、羧基(-COOH)等,从而制备出多基团纤维材料(NCS)。在一元和二元吸附体系中,考察了NCS对不同pH水体中铜/磺胺甲恶唑(SMZ-Cu)复合污染物的去除效果。Langmuir吸附等温线拟合结果表明,NCS对SMZ和Cu(Ⅱ)的最大理论吸附量分别为59.76 mg·g⁻¹和4.71 mg·g⁻¹,以及对络合物中SMZ和Cu(Ⅱ)的最大理论吸附量分别为56.21 mg·g⁻¹和5.54 mg·g⁻¹。吸附过程也符合准二级动力学方程,属于化学吸附。相比而言,NCS在一元吸附体系中更倾向单一吸附SMZ而不是Cu(II)。而且,多重相互作用使NCS在二元吸附体系中主要吸附SMZ-Cu为主,而不是单一污染物。密度泛函理论(DFT)计算不但验证了上述结果,还定量地解释在单一吸附系统中,NCS的-N⁺结构中-COOH与SMZ中磺酰氨氮结合最稳定,而C-N则与Cu结合能最大;在二元吸附体系中,最主要的吸附结构是SMZ-Cu以Cu接近NCS方式,而络合-解络合-再络合模式是该体系中Cu被吸附增加的原因。     

十六烷基三甲基溴化铵改性生物炭对水中镉离子吸附性能的影响

针对水体重金属污染治理问题,通过十六烷基三甲基溴化铵(CTAB)对竹炭(BC)、椰壳炭(CSC)进行改性, 采用傅里叶红外变换光谱(FT-IR)、扫描电镜(SEM)、X射线光电子能谱分析(XPS)和热稳定性分析(TGA)对改性前后的材料进行了表征,探究了投加量、pH对2种改性材料吸附去除水中镉离子性能的影响,并进行了动力学方程拟合及等温吸附模型拟合,探讨了CTAB改性前后活性炭吸附水中镉离子的机理。结果表明：2种CTAB改性材料基本结构虽未改变,但提升了竹炭(BC)和椰壳炭(CSC)的吸附性能,改性后材料的饱和吸附量分别为12.56 mg·g⁻¹(CTAB-BC)、10.71 mg·g⁻¹ (CTAB-CSC),较改性前分别提高了111%和92%;同时,CTAB-BC、CTAB-CSC的吸附量受pH影响较大,对二者的最适pH分别为4~7、6~7;CTAB-BC、CTAB-CSC均能较好地拟合准二级动力学方程(R²_CTAB-BC=0.999 9, R²_CTAB-CSC=0.993 7)及Langmuir模型(R²_CTAB-BC =0.970 3, R²_CTAB-CSC=0.976 8)。通过分析可知,CTAB-CSC、CTAB-BC 2种材料对含镉废水均有较好的去除效果。     

Removal of Pb2+ from aqueous solution by adsorption on chemically modified muskmelon peel

A cost-effective biosorbent was prepared by a green chemical modification process from muskmelon peel by saponification with alkaline solution of Ca(OH)₂. Its adsorption behavior for lead ions was investigated and found to exhibit excellent adsorption properties. Results showed that the optimal equilibrium pH range for 100 % adsorption is from 4 up to 6.4. Adsorption equilibrium was attained within 10 min. The adsorption process can be described well by Langmuir model and pseudo-second-order kinetics equation, respectively. The maximum adsorption capacity for lead ions was found to be 0.81 mol/kg. Pectic acid contained in the muskmelon peel is the main factor responsible for the uptake of lead ions onto the gel, and the chemical modification process presented in this study can be assumed effective to prepare other similar biomaterials. The large adsorption capacity and the fast adsorption rate indicated that chemically saponified muskmelon peel gel in present study has great potential to be used as a cost-effective adsorbent for the removal of lead ions from the water.     

Preparation of montmorillonite grafted polyacrylic acid composite and study on its adsorption properties of lanthanum ions from aqueous solution

Environmental Science and Pollution Research - Montmorillonite grafted polyacrylic acid composite (GNM) was prepared by using ultraviolet radiation grafting method in this work. The synthesized...     

Surfactant-assisted adsorption of uranyl ions in aqueous solution on TiO2/polythiophene nanocomposite

In this work, hexadecyltrimethylammonium-bromide (HTAB)-modified polythiophene (PTh)/TiO₂ nanocomposite (HTAB/PTh/TiO₂) was applied to remove uranyl ions (UO₂²⁺). FT-IR, XRD, ζ potential, TGA, SEM, and XPS were utilized to obtain the chemical and physical properties of HTAB/PTh/TiO₂. The effects of HTAB content, preparation temperature, and adsorption conditions on UO₂²⁺ removal were investigated comprehensively. And the UO₂²⁺ adsorption process on HTAB/PTh/TiO₂ was fitted to the Sips model with a saturated adsorption capacity of 234.74 mg/g, which was 6 times over TiO₂. The results suggested that the surfactant of HTAB can significantly improve the adsorption ability of TiO₂ for UO₂²⁺ ions. This work provides a strategy of surfactant modification for enhancing the separation and recovery ability of adsorbent toward UO₂²⁺ in the radioactive wastewater.

     

Selective removal of Cr(VI) from aqueous solution by adsorption on mangosteen peel

Mangosteen peel, rich in polyphenolic compounds, was used to prepare the adsorbent exhibiting highly selective adsorption for Cr(VI) over other metal ions such as Pb²⁺, Fe³⁺, Zn²⁺, Cd²⁺, and Cr³⁺ at the pH values of 1～4. The chemical modification method proposed by using calcium hydroxide is quite cost-effective and ecofriendly without using any toxic reagents or causing any secondary pollution. The adsorption isotherm results revealed that the adsorption of Cr(VI) on the gel fit well the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) at pH levels 1, 2, 3, and 4 was evaluated to be 2.46, 2.44, 1.99, and 2.14 mol/kg, respectively. The adsorption mechanism for Cr(VI) on the saponified gel was verified to follow an esterifiaction reaction coupled with the reduction of Cr(VI) to Cr(III) in which H⁺ plays a role of promoter. Thus, modified mangosteen peel gel has the prominent selectivity and low cost for Cr(VI) removal.     

Biosorption of lead(II) in aqueous solution by spent mushroom Tricholoma lobayense

The biosorption of lead(II) ions in both simulated and real wastewater by spent mushroom Tricholoma lobayense, was studied in this work. The results show a biomass with a high potential for removing lead ions from wastewater. The optimum pH for the adsorption is 4, and the adsorption process is fast. The best sorbent mass of the biomaterial is 5 g/L with an initial lead(II) concentration of 1 mmol/L. The process follows the Langmuir isotherm model, and the biosorption capacity of lead ions reaches to 210 mg/g, which is higher than many biosorbents previously studied. The mechanism of biosorption may be mainly attributed to ion exchange. The FT-IR study identifies the functional groups responsible for this process. A scanning electron microscope showed a significant change of the sorbent surface after the biosorption process. The energy dispersive elemental analysis also confirmed the adsorption of lead(II) ions.     

Selective separation of copper(II) and nickel(II) from aqueous media using the complexation-ultrafiltration process

The polyethylenimine (PEI) as complexing agent was used to study the complexation-ultrafiltration (CP-UF) process in the selective removal of Cu(II) from Ni(II) contained in aqueous media. Preliminary tests showed that optimal chemical conditions for Cu(II) and Ni(II) complexation by the PEI polymer were pH>6.0 and 8.0, respectively, and polymer/metal weight ratio of 3.0 and 6.0, respectively. The effect of some important operating parameters on process selectivity was studied by performing UF tests at different parameters: pH, polymer/metal weight ratio, transmembrane pressure (TMP), and membrane cut-off in a batch experimental set-up. It was observed that process selectivity was achieved by choosing the pH value for obtaining a preferential copper complexation (pH 6.0), and the polymer/metal ratio needed to bound only the copper ion (3.0). The selective separation by UF tests was performed by using both a laboratory aqueous solution and a real aqueous effluent (water from Emoli torrent, Rende (CS)). The Iris 30 membrane at TMP of 200 kPa (2 bar) for both aqueous media gave the best results. A complete nickel recovery was reached, and copper recovery was the highest for this membrane (94% and 92%). Besides at this pressure, a lower water amount was needed to obtain total nickel recovery by diafiltration. A little higher membrane fouling was obtained by using the river effluent due to the presence of dissolved organic and inorganic matter.