Uptake of aqueous heavy metal ions (HMIs) by various biomasses and non-biological materials: a mini review of adsorption capacities, mechanisms and processes

Author(s):  
Zhenzhen Yu ◽  
Qiming Jimmy Yu ◽  
Yi Wu ◽  
Kangle Ding
2011 ◽  
Vol 308-310 ◽  
pp. 178-181
Author(s):  
Xin Liang Liu ◽  
Li Jun Wang ◽  
Yong Li Chen ◽  
Nan Chen ◽  
Shuang Fei Wang

The bagasse fibers were activated by alkalize and etherified. 1,2-ethanediamine and carbon disulfide were used to modify the etherify fiber to get the chelate-fiber contained sulfur and nitrogen. The FTIR was used to characterize the xanthated aminating-fiber (XAF). The mechanism of sorption properties for heavy metal ions were studied. As the results shown, the optimal process to prepare the XAF was that the reaction time, concentration of NaOH and dosage of CS2 was 60min, 12% and 2mL, respectively. The chelate-fiber containing sulfur and nitrogen possessed high adsorption capacities for Cu(II) and the mechanism of sorption fitted the pseudo-second-order model well.


Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 112
Author(s):  
Kayee Chan ◽  
Kohki Morikawa ◽  
Nobuyuki Shibata ◽  
Anatoly Zinchenko

DNA–chitosan (DNA–CS) hydrogel was prepared by in situ complexation between oppositely charged DNA and chitosan polyelectrolytes via electrostatic cross-linking to study its adsorption characteristics. The DNA–chitosan hydrogel matrix contains (i) cationic (NH3+) and anionic (PO4–) sites for electrostatic binding with ionic species, (ii) -OH and -NH2 groups and heteroaromatic DNA nucleobases for chelation of heavy metal ions, and (iii) DNA double-helix for recognition and binding to small organic molecules of various structures and polarities. DNA–CS hydrogels efficiently bind with Hg2+, Pb2+, Cd2+, and Cu2+ metal cations of significant environmental concern. Adsorption capacities of DNA–CS hydrogels for studied metal ions depend on hydrogel composition and pH of solution and reach ca. 50 mg/g at neutral pHs. Hydrogels with higher DNA contents show better adsorption characteristics and notably higher adsorption capacity to Hg2+ ions. Because of the co-existence of cationic and anionic macromolecules in the DNA–CS hydrogel, it demonstrates an affinity to both anionic (Congo Red) and cationic (Methylene Blue) dyes with moderate adsorption capacities of 12.6 mg/g and 29.0 mg/g, respectively. DNA–CS hydrogel can also be used for adsorptive removal of pharmaceuticals on conditions that their molecules are sufficiently hydrophobic and have ionogenic group(s). Facile preparation and multitarget adsorption characteristics of DNA–CS hydrogel coupled with sustainable and environmentally friendly characteristics render this system promising for environmental cleaning applications.


2012 ◽  
pp. 335-342 ◽  
Author(s):  
Marina Sciban ◽  
Jelena Prodanovic ◽  
Radojka Razmovski

The tea fungus was found to have good adsorption capacities for heavy metal ions. In this work it was treated with HCl or NaOH at 20?C or 100?C, with the aim to improve its adsorption ability. The sorption of Cu(II) and Cr(VI) ions from aqueous solutions by raw and treated tea fungus was investigated in the batch mode. The largest quantity of adsorbed Cu(II), of about 55 mg/g, was achieved by tea fungus modified with NaOH at 100?C. For Cr(VI), the largest quantity of adsorbed anions, of about 58 mg/g, was achieved by the adsorbent modified with NaOH at 20?C. It was shown that acid modification of tea fungus biomass was not effective.


2014 ◽  
Vol 1056 ◽  
pp. 16-19
Author(s):  
Shu Li Ding ◽  
Dan Dan Hou ◽  
Bo Hui Xu ◽  
Yu Zhuang Sun

The Bentonite from Yongnian is Ca-Bentonite, Montmorillonite Content 52%, Colloidal Value 57ml/15g, Eca2+/CEC 53.60%. the Adsorption Characteristics of Pb2+, Cu2+ and Cr3+ onto Bentonite under Conditions of Constant Temperature and Ph have been Studied. the Results Show that the Adsorption Capacities of Heavy Metal Ions onto Bentonite from Yongnian Follow the Order of Pb2+> Cu2+> Cr3+. it is Found that the Adsorption Process of Bentonite Accords with the Langmuir Isotherm Model. the Maximum Adsorption of 3 Kinds of Metal Ions onto Bentonite is in Order of Cr3+>Cu2+>Pb2+.


Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2482 ◽  
Author(s):  
Janek Weißpflog ◽  
Alexander Gündel ◽  
David Vehlow ◽  
Christine Steinbach ◽  
Martin Müller ◽  
...  

The biopolymer chitosan is a very efficient adsorber material for the removal of heavy metal ions from aqueous solutions. Due to the solubility properties of chitosan it can be used as both a liquid adsorber and a solid flocculant for water treatment reaching outstanding adsorption capacities for a number of heavy metal ions. However, the type of anion corresponding to the investigated heavy metal ions has a strong influence on the adsorption capacity and sorption mechanism on chitosan. In this work, the adsorption capacity of the heavy metal ions manganese, iron, cobalt, nickel, copper, and zinc were investigated in dependence on their corresponding anions sulfate, chloride, and nitrate by batch experiments. The selectivity of the different heavy metal ions was analyzed by column experiments.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Qiang-ling Yao ◽  
Ze Xia ◽  
Chuan-jin Tang ◽  
Liu Zhu ◽  
Wei-nan Wang ◽  
...  

Coal mine goafs can be used to store and purify mine water; therefore, they are important for mitigating the environmental impact of mining on ecologically fragile areas in Western China. Coal gangue in goafs can reduce turbidity, suspended matter, total hardness, and chemical oxygen demand (COD) in mine wastewater. Because gangue in goaf areas is rich in clay minerals, they serve as ion exchange sites. We investigated the adsorption of heavy metal ions by silty mudstones in the Ulan Mulun mine. The adsorption kinetics and isothermal adsorption characteristics of four heavy metal ions, i.e., Pb(II), Cd(II), Cr(III), and Mn(II), were investigated using batch experiments. Under a pH of 6.75 and temperature of 20°C, the adsorption capacity of silty mudstone particles (<74 μm) was 6.3012 g, 1.5701, 1.2571, and 1.3729 mg/g for Pb(II), Cd(II), Cr(III), and Mn(II), respectively. Based on the experimental results, quantitative relationships between the adsorption quantity per unit of rock surface and the equilibrium concentration of heavy metals in solution were developed using Langmuir, Freundlich, and D–R equations. The relationships were used to obtain the equilibrium concentration of the solution. Finally, the ratio of the f value of the water-rock contact area in the goaf to the water volume was calculated and analyzed. The f value was inversely proportional to the average vertical opening of gaps between gangues in the goaf. The adsorption rate functions for Pb(II), Cd(II), Cr(III), and Mn(II) in the goaf were obtained, and the corresponding adsorption capacities were calculated. The adsorption capacities were controlled by the f value and adsorption properties of the gangue. These results can be used in future studies on mine wastewater treatment.


2002 ◽  
Vol 20 (7) ◽  
pp. 607-617 ◽  
Author(s):  
Adil Denizli ◽  
Bora Garipcan ◽  
Sibel Emir ◽  
Süleyman Patir ◽  
Ridvan Say

Details of the adsorption performance of poly(2-hydroxyethylmethacrylate–methacrylamidocysteine) [p(HEMA–MAC)] beads towards the removal of heavy metal ions from aqueous solution were studied. The metal-complexing ligand and/or co-monomer MAC was newly synthesized from methylacrylochloride and cysteine. Spherical beads of average size 150–200 mm were obtained by the radical suspension polymerization of MAC and HEMA conducted in an aqueous dispersion. The p(HEMA–MAC) beads obtained had a specific surface area of 18.9 m2/g. p(HEMA–MAC) beads were characterized by swelling studies, FT-IR spectroscopy and elemental analysis. Such beads with a swelling ratio of 72%, and containing 3.9 mmol MAC/g, were used for heavy metal removal studies. The adsorption capacities of the beads for selected metal ions, i.e. CdII, AsIII, CrIII, HgII and PbII, were investigated in aqueous media containing different amounts of these ions (10–750 mg/l) and at different pH values (3.0–7.0). The adsorption rate was fast in all cases. The maximum adsorption capacities of the p(HEMA–MAC) beads were 1058.2 mg/g for CdII, 123.4 mg/g for AsIII, 199.6 mg/g for CrIII, 639.1 mg/g for PbII and 1018.6 mg/g for HgII. On a molar basis, the following affinity order was observed: CdII > HgII > CrIII > PbII >AsIII. The adsorption capacity of the MAC-incorporated beads was affected significantly by the pH value of the aqueous medium. The adsorption of heavy metal ions from artificial wastewater was also studied. In this case, the adsorption capacities were 52.2 mg/g for CdII, 23.1 mg/g for CrIII, 83.4 mg/g for HgII, 62.6 mg/g for PbII and 11.1 mg/g for AsIII at an initial metal ion concentration of 0.5 mmol/l. The chelating beads could be regenerated easily with a higher effectiveness by 0.1 M HNO3. These features make p(HEMA–MAC) beads potential candidates for heavy metal ion removal at high capacity.


Author(s):  
Jyotikusum Acharya ◽  
Upendra Kumar ◽  
P. Mahammed Rafi

Heavy metal remediation of aqueous streams is of special concern due to recalcitrant and persistency of heavy metals in environment. Conventional treatment technologies for the removal of these toxic heavy metals are not economical and further generate huge quantity of toxic chemical sludge. Agricultural waste materials being economic and ecofriendly due to their unique biochemical composition, availability in abundance, renewable, low in cost and more efficient are seem to be viable option for heavy metal remediation. The major advantages of biosorption over conventional treatment methods include: low cost, high efficiency, minimization of chemical or biological sludge, regeneration of biosorbents and possibility of metal recovery. It is well known that cellulosic waste materials can be obtained and employed as cheap adsorbents and their performance to remove heavy metal ions can be affected upon chemical treatment. In general, chemically modified plant wastes exhibit higher adsorption capacities than unmodified forms. The functional groups present in agricultural waste biomass viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. Have affinity for heavy metal ions to form metal complexes or chelates. Some of the treated adsorbents show good adsorption capacities for Cd, Cu, Pb, Zn and Ni. Rice husk as a low-value agricultural by-product can be made into sorbent materials which are used in heavy metal removal. The mechanism of biosorption process includes chemisorptions, complexation, adsorption on surface, diffusion through pores and ion exchange etc. Agricultural residues are lignocelluloses substances which contain three main structural components: hemicelluloses, cellulose and lignin. Lignocellulosic materials also contain extractives. Generally, three main components have high molecular weights and contribute much mass, while the extractives is of small molecular size, and available in little quantity, which announce in heavy metal removal.


2016 ◽  
Vol 675-676 ◽  
pp. 154-157 ◽  
Author(s):  
Itsaraporn Pengsaket ◽  
Kheamrutai Thamaphat ◽  
Pichet Limsuwan

Many researchers have currently interested in using Fe3O4 magnetic nanoparticles (MNPs) impregnated onto agricultural wastes for removal of heavy metal ions in wastewater treatment process. In this work, the MNPs-pomelo peel powder (MNPs-PP) composites were developed and their adsorption capacities of heavy metal ions were studied as well. The MNPs-PP samples were synthesized by co-precipitation method in different ratios; 2:1, 2:2, 2:4, 2:5, and 2:6 (by weight). The results showed that the as-synthesized MNPs were mainly spherical shape with an average particle size of approximately 12.7 ± 0.6 nm. Then, the MNPs, PP and MNPs-PP in different ratios were used as adsorbents for adsorption of 25 ppm Cu2+ in aqueous solution. The pH and temperature of solution were kept constant at 5 and 30 °C, respectively. From the experiment, it was found that the adsorption capacities decreased in the following order: PP > MNPs-PP (2:6) > MNPs-PP (2:5) > MNPs-PP (2:4) > MNPs-PP (2:2) > MNPs-PP (2:1) > MNPs. It indicated that the adsorption capacity of as-synthesized MNPs-PP is significantly higher than that of sole MNPs. Furthermore, the adsorption capacities of MNPs-PP increased with increasing the weight ratio of PP. The MNPs-PP developed herein has demonstrated not only high adsorption efficiency but also have shown additional benefits such as ease to synthesis, cost-effectiveness, environmental-friendliness, and ease to separate from treated water by an external magnet.


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