Adsorption Of Zn Research Articles

Comparative study of solvothermal and catalytic solvothermal carbonization of rice husk for Fe(iii), Zn(ii), Cu(ii), Pb(ii) and Mn(ii) adsorption, kinetics, surface chemistry and reaction mechanism

Schematic diagram of solvochars/catalytic solvochar production and application for multi-heavy metal ion adsorption.

Gidya, Leonardit ve Kompost’un Çinko Sorpsiyon Özelliklerinin Belirlernmesi

Leonardite and compost are used as soil conditioner materials. Gyttja is a material which contains 30-40% lime and 40-50% organic matter with a reserve of approximately 4.8 billion tons in Afşin-Elbistan Thermal Power Plant basin. These materials are used in the production of organomineral (OMG) fertilizers. Zinc (Zn) is one of the micronutrients that plants need. Available Zn deficiency is observed in approximately 49% of Turkish soils. The aim of this study was to determine the Zn adsorption properties of gyttja, leonardite and compost used in OMG fertilizer production. The study was conducted under laboratory conditions. In order to determine the optimum adsorption conditions, the effect of pH, particle size, temperature, shaking time and solution concentration were determined. Then, adsorption properties were determined using linear Langmuir isotherm under optimum conditions. According to Langmuir isotherm, the maximum sorption capacity (qmax) was found to be 14.10 mgg-1 for gyttja, 13.74 mgg-1 for leonardite and 15.67 mgg-1 for compost. In conclusion, Zn sorption values of gyttja, leonardite and compost were consistent with Langmuir and Freunlich isotherms. The maximum sorption capacity (qmax) of these materials is very close to each other. When these data are taken into consideration, it is seen that 1 kg of organic material can sorbed about 15 g Zn. It is useful to take these basic data into account in OMG fertilizer production and sustainable Zn fertilization.

Synthesis, characterization and adsorptive performance of CuMgAl-layered double hydroxides/montmorillonite nanocomposite for the removal of Zn(II) ions

Developing an effective adsorbent for removing heavy metals is an interesting field in water and wastewater treatment research. This work successfully prepared and used a CuMgAl-layered double hydroxide/montmorillonite nanocomposite (CuMgAl-LDH/MMt) for the adsorption of heavy metal pollutants from an aqueous solution. The nanocomposite had a maximum adsorption capacity of 154.21 mg/g for Zn(II) ion adsorption. The Langmuir model and pseudo-second-order kinetic model presented a better fit for the Zn(II) adsorption process. The mechanism of Zn(II) adsorption mainly involves exothermic and spontaneous processes. Moreover, the effects of solution pH, pollutant concentration, adsorbent dose, temperature, and repeated use of CuMgAl-LDH/MMt on the Zn(II) adsorption were tested, revealing that CuMgAl-LDH/MMt has excellent stability and the ability to remove Zn(II) The maximum removal rate (95.1 %) was determined under conditions of pH = 5, CuMgAl-LDH/MMt dosage = 0.25 g per100 ml Zn(II) solution, particle size of adsorbent = 87 µm, shaking speed = 200 rpm, temperature = 25 °C, initial concentration = 70 mg/L, and adsorption time = 90 min. In conclusion, this study demonstrates the value of CuMgAl-LDH/MMt as the best adsorbent for the removal of Zn(II) ions from wastewater compared to other adsorbents used for the same purpose.

Changes in Desulfovibrio desulfuricans sub sp EPS components and adsorption performance under exogenous sulfur induction and its mediation role in the biosynthesis of ZnS QDs

Sulfate Reducing Bacteria(SRB) can remove heavy metal ions by producing metal sulfide precipitation, which has aroused the research interest of scholars recently. For SRB, exogenous sulfur is one of the most important nutrients, however, there are few reports about the impact of exogenous sulfur on SRB, especially its EPS. Here, we investigated the inducible effect of sulfur sources (Na2SO4, Na2SO3, and Na2S2O3·H2O) on EPS production from SRB for the first time. The results found that exogenous sulfur can significantly increase the production of EPS, especially protein. The increased functional groups(C–O/C–N, CN) in the protein are favorable to adsorption of more heavy metals. Moreover, S2– was added to the system after adsorption of Zn(II) for the biosynthesis of ZnS QDs from the resource recovery point. The experiments and tests showed the yield of cubic β-ZnS QDs correlated with the amount and adsorption performance of EPS. The PL spectrum of EPS present red-shifted and enhanced antibacterial properties due to the adhesion of EPS to ZnS QDs, the basic amino acid His in EPS played an important role in the adsorption of Zn(Ⅱ) and the nucleation of ZnS QDs. This research brings new horizons for using EPS to treatment heavy metal wastewater and resource recycling.

Application of sulphate and magnesium enriched waste rapeseed cake biochar for recovery of Cu(II) and Zn(II) from industrial wastewater generated in sulphuric acid plants

The development of an efficient and green adsorbent is of great significance for copper(II) and zinc(II) removal and recovery from industrial wastewater. In this study, for the first time, waste rapeseed cake is used as a biosource to synthesize MgO-SO3 enriched biochar. The newly developed adsorbent was produced in a one-step process by pyrolysis at 973.15 K for 2 h, under anoxic conditions. Porous structure, specific surface area, and composition of biochar were studied. Furthermore, sorption properties of the obtained biochar in relation to copper(II), zinc(II), and arsenic(III) ions were also studied. The impact of parameters such as: sorption time, temperature, adsorbate concentration, sorbent mass, and solution pH on the efficiency of the adsorption process of the studied cations was examined. Rapeseed cake biochar exhibits good Cu(II) adsorption capacity (90.4 mg g−1) with a short equilibrium time (4 h), which indicates the competitiveness to similar adsorbents. The adsorption of Cu(II) on the biochar was more consistent with the pseudo-second-order kinetic models and Langmuir model. The Freundlich and pseudo-second-order kinetic models best fitted the removal of Zn(II) by modified biochar. The mechanism of Cu(II) and Zn(II) adsorption was also postulated. Experimental data collected have shown that the presence of arsenic(III) at higher concentrations adversely affects the sorption efficiency of Cu(II) and Zn(II) ions. Thus, this study shows that the sorbent can be successfully used for the separation of Cu(II) and Zn(II) from technological wastewaters. A flowsheet for the proposed process is presented.

A DFT-based analysis of adsorption performance of Zn2+ on vacancy defected carbon nanotubes

In this paper, the adsorption performance of Zn2+ on the vacancy defected carbon nanotube (V-CNT) was studied by using the first-principles calculation based on density functional theory. The results showed that, compared with the pristine carbon nanotube (P-CNT), the final adsorption distance between the V-CNT and Zn2+ was considerably decreased, while the adsorption energy and charge transfer amount between them were greatly increased. These results, along with a computing on the charge density, all indicated that the adsorption of Zn2+ on the V-CNT was chemisorption. Analysis on the partial density of states confirmed the formation of orbital hybridization between the V-CNT and Zn2+. In addition, the energy gap of the V-CNT was decreased significantly after the adsorption of Zn2+. Therefore, vacancy defected carbon nanotubes have a great application potential in the detection and adsorption of Zn2+ ions in wastewater.

Influence of the surface modification of granular-activated carbon synthesized from macauba on heavy metal sorption.

Adsorption on activated carbon is a promising technique for the treatment of low-concentration heavy metal pollutants in water with high efficiency and simple operation. However, commercial-activated carbon is often associated with high costs. Therefore, much attention has been given to activated carbon derived from low-cost agricultural and residual biomass. In this work, adsorption of Zn, Cd, and Pb ions in aqueous solutions was conducted using granular-activated carbon obtained from macauba palm, biomass waste of biofuel production, after surface modification using different methods. The adsorbents were obtained in granular form which facilitates all steps of the use, recovery, and reuse of the material, differently from the powdered-activated carbon normally used. The materials were characterized by using XPS, elemental analysis, N2 sorption (BET method), and zeta potential measurements. Such techniques allowed observation of the functionalization of the carbon surface. The materials presented high adsorption capacities when compared to other works in the literature, with a capacity of approximately 7.69, 8.42, and 1.63mmolg-1 for Zn2+, Cd2+, and Pb2+, respectively. In addition, the materials showed a high capacity to be reused, removing 75% of Pb and 99% of both Cd and Zn after 4 cycles.

Chemical Fractionations of Lead and Zinc in the Contaminated Soil Amended with the Blended Biochar/Apatite.

Heavy metal contamination in agricultural land is an alarming issue in Vietnam. It is necessary to develop suitable remediation methods for environmental and farming purposes. The present study investigated the effectiveness of using peanut shell-derived biochar to remediate the two heavy metals Zn and Pb in laboratory soil assays following Tessier's sequential extraction procedure. The concentration of heavy metals was analyzed using Inductively coupled plasma mass spectrometry (ICP-MS). This study also compared the effectiveness of the blend of biochar and apatite applied and the mere biochar amendment on the chemical fractions of Pb and Zn in the contaminated agricultural soil. Results have shown that the investigated soil was extremely polluted by Pb (3047.8 mg kg-1) and Zn (2034.3 mg kg-1). In addition, the pH, organic carbon, and electrical conductivity values of amended soil samples increased with the increase in the amendment's ratios. The distribution of heavy metals in soil samples was in the descending order of carbonate fraction (F2) > residue fraction (F5) > exchangeable fraction (F1) > Fe/Mn oxide fraction (F3) > organic fraction (F4) for Pb and F5  ≈  F2 > F1 > F3 > F4 for Zn. The peanut shell-derived biochar produced at 400 °C and 600 °C amended at a 10% ratio (PB4:10 and PB6:10) could significantly reduce the exchangeable fraction Zn from 424.82 mg kg-1 to 277.69 mg kg-1 and 302.89 mg kg-1, respectively, and Pb from 495.77 mg kg-1 to 234.55 mg kg-1 and 275.15 mg kg-1, respectively, and immobilize them in soil. Amending the biochar and apatite combination increased the soil pH, then produced a highly negative charge on the soil surface and facilitated Pb and Zn adsorption. This study shows that the amendment of biochar and biochar blended with apatite could stabilize Pb and Zn fractions, indicating the potential of these amendments to remediate Pb and Zn in contaminated soil.

Removal of Heavy Metals (Pb2+, Zn2+, Cu2+, Hg2+, Co2+, Cr2+ and Cd2+) From Water by Trimethyl Phenyl Ammonium Cation (TMPA+) Based Organoclay: Experimental and Statistical Test

In this study, trimethyl phenyl ammonium cation (TMPA+) intercalated bentonite was used as an adsorbent for adsorptive removal of seven heavy metal ions namely: Pb (II), Zn (II), Cu (II), Hg (II), Cr (II), Co (II) and Cd (II) in aqueous solution via batch adsorption process. The developed adsorbent, ab initio has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The operational parameters evaluated on the adsorption efficiency were solution pH, initial metal ions concentration, temperature, adsorbent dosage, and contact time. The adsorption of Pb (II), Zn (II), Cu (II), Hg (II), Cr (II), Co (II) and Cd (II) ions were found to have attained equilibrium positions in 120 min for the concentration range tested, respectively. Two generally applied linearized adsorption isotherm models; Langmuir and Freundlich tested, when compared, revealed that Langmuir isotherm fitted well to the experimental data judging from the higher correlation coefficient values (R2 ) and lower values of the error functions (chi-square (χ2), the sum of square error (ERRSQ/SSE) and the sum of absolute error (EABS)) with monolayer adsorption capacities of 17.66, 21.12, 14.64, 14.98, 16.60, 13.81 and 15.50 mg/g for Pb (II), Zn (II), Cu (II), Hg (II), Cr (II), Co (II) and Cd (II) ions, respectively. Adsorption kinetic models investigated by pseudo-first-order and pseudo-second-order showed the conformity of pseudo-second-order model to the process of adsorption as informed by the higher values R2 and Adj, R2 , maximum log-likelihood and smaller ERRSQ/SSE, χ2, Akaike information criterion (AIC), Bayesian information criterion (BIC), and Hannan-Quinn information criterion (HQIC). Result from kinetic data revealed the adsorption mechanism of Pb (II), Zn (II), Cu (II), Hg (II), Cr (II), Co (II) and Cd (II) ions onto Bt-TMPA as a chemical adsorption.

Adsorption of Phosphate and Heavy Metals by Lanthanum Modified Zeolite and Its Performance in Sediment Inactivation

Due to the large scale of mining and smelting activities, considerable amounts of heavy metals are discharged into the environment and accumulate in the sediment of rivers and lakes. The combined pollution of heavy metals and the intrinsic phosphorus in sediment calls for novel remediation technologies. In this study, lanthanum-modified zeolite (LMZ) was employed as an inactivation agent for the immobilization of phosphorus, zinc, and lead in sediments. The adsorption capacities as well as the inactivation performance of LMZ for P, Zn, and Pb were investigated, and the adsorption mechanisms were explored via desorption experiments, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The results indicated that the adsorption maximums of LMZ for P, Zn, and Pb were 53.76, 27.70, and 123.45 mg·g-1, respectively. Pre-adsorption of Zn and Pb had a negligible effect on the P adsorption by LMZ, whereas the adsorption of Zn and Pb were inhibited significantly by the pre-adsorption. P, Zn, and Pb in the sediment were transformed to more stable or less bioavailable forms by dosing 0.83% and 1.66% weight percentages of LMZ. It was found that P, Zn, and Pb were adsorbed through the formation of inner-sphere complexes. Further, desorption experiments and XRD patterns suggested that electrostatic attraction and surface precipitation also contributed to the adsorption of Zn and Pb, respectively.

Adsorption of Zn(II) on Pristine and SPLP/TCLP Leached Rice Straw Biochar: an Interplay of Precipitation and Ion Exchange

Adsorption of Zn(II) on Pristine and SPLP/TCLP Leached Rice Straw Biochar: an Interplay of Precipitation and Ion Exchange

Adsorption efficiency of heavy metals (Fe and Zn) in open pit water using Fe3O4/SiO2 nanocomposite from kaolin Bangka

ABSTRACTHeavy metals such as Fe and Zn are the dominant heavy metals contained in open pit water. One of the efforts to reduce the level of heavy metal contamination in waters is the adsorption process using nanomaterials. The adsorption of Fe and Zn in open pit water has been carried out using Fe3O4/SiO2 nanocomposites from Kaolin Bangka. Based on XRD characteristics, it shows Fe3O4/SiO2 30% has the smallest average particle size, namely 41.68 nm. The resulting adsorption efficiency is 83.15% for Fe metal and 33.33% for Zn metal.

Removal of Cu, Pb and Zn from stormwater using an industrially manufactured sawdust and paddy husk derived biochar

Direct flow of untreated stormwater containing Cu, Pb and Zn is of immediate concern to aquatic life in waterways. To date, most biochar used has been synthesized under controlled laboratory conditions using furnaces purged with inert gasses. In this study, the removal of Cu, Pb and Zn using biochar synthesized using paddy husk and sawdust feedstocks has used an industrial scale double chamber downdraft pyrolysis reactor. The effect of pyrolysis temperature and the effect of feedstock in the removal of Cu, Pb and Zn was evaluated by conducting batch adsorption experiments. Synthesized adsorbent materials were characterized using proximate analysis, zero-point charge, scanning electron microscopy, X-ray diffraction and Fourier Transform infrared spectroscopy. The biochar yield was in a lower range compared with the literature attributed to the higher heating rate (50 °C/min) in the pyrolizer. Maximum removal efficiencies were observed when the initial pH was at the value closest, when below the solubility limit for the heavy metals. The paddy husk biochar and sawdust biochar synthesized in the temperature range 350–450 °C and 450–550 °C performed best in the removal of the three heavy metals. Chemisorption was the main mechanism for the removal of the three heavy metals. The maximum adsorption capacities of Cu and Zn were 10.27 and 6.48 mg/g was achieved with paddy husk biochar and a maximum Pb adsorption capacity of 17.57 mg/g was achieved by sawdust biochar. Surface complexation, co-precipitation, p-electron interactions, physical adsorption and surface precipitation were the main mechanisms of removal of the three heavy metals. • Maximum adsorption of Cu, Pb and Zn was 10.27, 17.57 and 6.48 mg/g, respectively. • Removal of Cu and Zn depends on interaction with surface and functional groups. • Surface complexation and coprecipitation interactions was main mechanisms.

Deposition of Horizontally Stacked Zn Crystals on Single Layer 1T‐VSe2 for Dendrite‐Free Zn Metal Anodes

AbstractOwing to the moderate redox potential and high safety, Zn metal anodes have been garnering great attention. However, the poor reversibility and limited‐service period caused by side reactions and dendrites hinder their applications. Here, a novel anode material consisting of a hexagonal 1T‐Vanadium diselenide (1T‐VSe2) film on graphene is developed as a zincophilic template to epitaxially electrodeposit hexagonal closest packed Zn to replace the conventional metal substrates in Zn batteries. The 1T‐VSe2/Zn anode induces a horizontally (002)‐oriented plate‐like Zn crystal deposition morphology instead of randomly oriented grains that prompts the compact Zn deposition. According to density functional theory calculations, the VSe2 substrate exhibits a higher Zn adsorption (−0.54 eV) than the graphene (−0.38 eV) or neat Zn (−0.48 eV) counterparts, leading to the enhanced zincophilicity and a lower nucleation overpotential, in agreement with the experimental results. The force field‐based molecular dynamics simulations visualize Zn nucleation and morphological evolution at the atomistic level. The rapid adatom diffusion on VSe2 leads to layer‐by‐layer Zn electrodeposits with higher fraction of the (002) facets to effectively prohibit dendrite formation. The symmetric cell with 1T‐VSe2/Zn delivers an ultra‐stable cyclic life of 2500 h with 50 mV overpotential at 1 mA cm−2 and 1 mAh cm−2.

Interaction of Zinc Ions with Hydrated Calcium Silicate Surfaces

Cement materials with calcium silicate hydrate (CSH) gel as the main hydration product have good ability to immobilize heavy metal contaminants. In order to fundamentally understand the curing mechanism of cement materials, the atomic intensity distribution, kinetic properties of Zn2+ ions near the interface of CSH gels were investigated by molecular dynamics method by building a realistic CSH gel nanopore model and aqueous Zncl2 solution. The simulation results show that the interaction between zinc ions and hydrated calcium silicate surface is mainly through the desorption of calcium ions, which leads to the negative charge of the whole hydrated calcium silicate matrix, and thus the adsorption of Zn2+ by coulombic force, and thus the immobilization effect of Zn2+.

Optimization of coal fly ash-based porous geopolymer synthesis and application for zinc removal from water

Coal fly ash-based porous geopolymer (CFAPG) is a potential adsorbent for heavy metal-contaminated water remediation and can also mitigate the accumulation of coal fly ash from thermal power plants. Production parameters influence the physicochemical properties (e.g., adsorption capacity) of CFAPG. Ten potential factors involved in the CFAPG production process were examined using a Plackett-Burman design (PBD) and then an orthogonal experimental design (OED). The results show the alkali activator modulus (MS), alkali-ash mass ratio (AA), foaming agent-ash mass ratio (FAR), and sodium dodecyl sulfate-ash mass ratio (SDSA) were the most important factors influencing the Zn adsorption capacity of CFAPG. Ternary plots confirm the interaction between these four factors, with the role of FAR being easily masked by other factors and MS being the least influenced by other factors. Furthermore, Zn adsorption on the CFAPG created with optimal parameters was best described by the Bi_Langmuir model, indicating two different sorption site classes on the surface of CFAPG with a total maximum Zn adsorption capacity of 13.42 mg g−1. These results provide key parameters for the production of geopolymers as heavy metal adsorbents.

Effect of solutes on the performance of Zn-coating and Zn-inducing transgranular cracking in steel based on DFT calculations

The effect of solutes, Co, Cu, Cr, Mn, Mo, Nb, Ni, Ta, Ti, V and Zr, in steel on the penetration properties of Zn and stability of surface or matrix were explored theoretically using density functional theory method, and the role of solutes in the Zn-coated surface and Zn-induced transgranular fracture performance was considered. The effect of solution on α-Fe are more obvious than that on γ-Fe, they significantly change surface energy value and the order of stability of low-index surface in α-Fe. The segregation energies of solutes were calculated and concluded that most of selected elements possibly segregate to the surface from the matrix. The study about Zn adsorption properties found that Zn atoms is energetically favorable to absorb at the (001) surface layer in α-Fe, and the segregation of Zr, V, Nb and Ta are helpful to the process of Zn-coating and increase the stability of Zn-coated surface. In addition, the solutes in the matrix increase the difficulty of transgranular fracture. Although the surrounding of solutes is the preference site for cracking occurring and propagation, alloying is found to lead to a general increase in the cleavage energy of α-Fe during Zn penetration, suggesting a reduction in the tendency for transgranular fracture. Therefore, it is feasible that the addition of Zr, V, Nb and Ta as alloy element in steel to improve the properties of Zn-coating and inhibit the occurrence of Zn-inducing transgranular cracking. Our results are helpful to understand and design AHSSs inhibiting LME susceptibility.

Rapid adsorption of some heavy metals using extracted chitosan anchored with new aldehyde to form a schiff base.

A new aldehyde 2,2’-[propane-1,3-diylbis(oxy)] dibenzaldehyde was synthesized from refluxing 2-hydroxy acetophenone and 2-hydroxy 1,3-dichloropropanean in an alcoholic medium. The compositions and properties of the new aldehyde compound were characterized by elemental analysis, FTIR, and nuclear magnetic resonance spectroscopy studies. The extracted chitosan was made to react with a new aldehyde to form a Schiff base by a suitable method. The effects of initial concentration of metal ions, exposure time, imine weight, and pH on the adsorption of Cu(II), Cr(III), and Zn(II) metal ions were examined. An adsorption batch experiment was conducted. The adsorption process followed a second-order reaction and Langmuir model with qe 25 mg/g, 121 mg/g, and 26.31 mg/g for Cu(II), Zn(II), and Cr(III) respectively. The Gibbs free energy showed a negative value and the adsorption/desorption tests provided a high value 5 times.

Enhanced Zn(II) adsorption by chemically modified sawdust based biosorbents.

Heavy metals present in industrial effluents, when discharged into water channels, not only affect humans but also negatively impact plants and aquatic organisms. Sawdust is available readily in developing countries and can be used by small-scale industries for effluent water treatment containing low concentrations of bivalent zinc ions. This study explores the potential of sawdust-derived biosorbents, after boiling (SDB), chemical modification with formaldehyde (SDF), and sulfuric acid (SDS), for sequestration of Zn(II) from simulated wastewater as well as industrial effluents. The morphological analysis of the three biosorbents indicated a suitable porous structure with a pore size of 232.928 m2/g (SDB), 291.102 m2/g (SDF), and 498.873 m2/g (SDS). The functional analysis of native and metal-laden biosorbents indicated the role of - OH, - C = O, and - NH functional groups in Zn(II) binding. The process parameters were optimized and the spontaneous adsorption of Zn(II) was found to proceed by multilayer formation by following pseudo-second-order kinetics. SDS adsorbent (0.1g) exhibited a greater potential for removal of Zn(II) from industrial effluents as compared to SDB and SDF at pH = 6.0 with the equilibrium adsorption capacity of 45.87mg/g. Therefore, SDS could be a promising adsorbent for the treatment of wastewater in small-scale industries.

Comparative assessment of the biomass solar pyrolysis biochars combustion behavior and zinc Zn(II) adsorption

Biochars from solar pyrolysis of the waste straw, and dried sewage sludge, were assessed to recognize the possible application as unconventional adsorbents and fossils replacements for combustion purposes. The adsorption properties of the biochars were characterized by the BET (Brunauer, Emmett, and Teller) surface area, pore volumes, and the degree of Zn(II) adsorption from aqueous solutions. A higher removal degree of zinc ions of 26% was noted for biochars from dried sewage sludge with a BET area of 40.84 m2/g, compared to the waste straw biochars with a BET area of 1.67 m2/g and a corresponding removal degree of 16%. Both biochars presented more uniform combustion behavior compared to raw biomass, with the ignition and burnout temperatures similar to coal. Solar pyrolysis caused a reduction of the combustion kinetic steps, from multi-step combustion of the raw biomass to a single-step and two-step kinetic mechanisms for the sewage sludge and waste straw biochars respectively. It was found that the waste straw biochars are possible alternative fuels with a higher heating value of 22.6 MJ/kg, while sewage sludge chars presented better zinc adsorption of 2.09 mg/g and a total removal degree of 26%.