Removal Of Zn Research Articles

Novel Polymer Sorbents with Imprinted Task-Specific Ionic Liquids for Metal Removal.

In this paper, the potential of novel polymer sorbents with the imprinted IL-functional group for the removal of Cu(II), Cd(II), and Zn(II) from aqueous solutions was investigated by batch mode. The sorbents were fabricated by direct reaction of the prepared polymer matrix (poly(vinylbenzyl chloride-divinylbenzene), VBC, and poly(vinylbenzyl bromide-divinylbenzene), VBBr) with 1-(3- or 4-pyridyl)undecan-1-one and oxime of 1-(3- or 4-pyridyl)undecan-1-one. The Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy (Raman), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) techniques were used to show functionality and stability of the sorbents. The materials were also characterized by contact-angle goniometry, X-rayphotoelectron spectroscopy (XPS), and Zeta potential analysis. The removal of Cd(II), Cu(II), and Zn(II) was monitored and optimized under the influence of several operational controlling conditions and factors such as pH, shaking time, temperature, initial metal ions concentration, and counter-ions at the functional group. The results obtained confirmed the very high potential of the sorbents; however, the properties depend on the structure of the functional group. The tested sorbents showed fast kinetics, significant capacity at 25 °C (84 mg/g for the Zn(II) sorption with VBC-Ox4.10, 63 mg/g for the Cd(II) sorption with VBBr-Ox3.10, and 69 mg/g for the Cu(II) sorption with VBC-K3.10), and temperature dependence (even 100% increase in capacity values at 45 °C). The selected sorbent can be regenerated without a significant decrease in the metal removal efficiency.

Biosorption of zinc from aqueous solution using algae and plant biomass

In the present study, the sorption capacity of plant biomass has been studied; particularly the ability of biomass algae Chlorella vulgaris, filamentous green algae Spirogyra sp. and roots, stems and leaves of an invasive plant Reynoutria japonica to bind up Zn2+ ions. The results of this biosorption study revealed that the rate and extent of uptake were affected by pH level, contact time and initial metal concentration. The maximum uptake of metal ions was obtained at pH 6.0. The equilibrium sorption data for metal system at pH 6 were described by the Langmuir isotherms model. For Zn2+, sorption capacity qmax of 17 mg/g was achieved using biomass from leaves. Removal of Zn2+ with 1g of biosorbent from leaves was almost 77% when present in low concentrations, whereas it is lower at higher concentrations.

Application of biohydrometallurgical processes for heavy metals removal from acid mine drainage

The main scope of this study was to remediate Acid Mine Drainage (AMD) by application of biohydrometallurgical processes, environmentally friendly, to remove heavy metals such as Zn, Cu, Mn, Cd, Al and Fe. The processes studied have been electrowinning and bioprecipitation. The samples utilised were collected from the zinc mine located in Italy and from a cooper – iron ore deposit in Slovakia. By electrochemical experiments, high metals removal, with a low energetic consumption, has been achieved: in particular, by Zn electrodeposition, it was possible to achieve 95-99% Zn removal. Culture of sulphatereducing bacteria (SRB) of genera Desulfovibrio sp. was used for the bioprecipitation tests. The precipitation kinetic of metals at the original pH of aforementioned AMD by SRB has been investigated. This method has been performed in two interconnected reactors. Achieved results indicate the 98-99% selective elimination of Cd from AMD - Italian mine, and the 98-99% selective elimination of Cu from AMD - Slovak mine by bacterially produced H2S. Both the electrowinning and bioprecipitation processes have been demonstrated the technical feasibility to decrease the heavy metals concentration. The experimental work has been carried out in the framework of the agreement of scientific cooperation between the Institute of Environmental Geology and Geoengineering of the CNR, Italy and the Institute of
 Geotechnics of Slovak Academy of Sciences, Slovakia (years 2007-2009).

Removal of heavy metals from textile industry wastewater

Wastewaters of several industries such as textile, leather or dye etc., contain dangerous and toxic compounds, even some of which are potential carcinogenics. Considering the volume and composition, wastewaters of the textile industry have much more polluting characteristics compared to other industries. Although treatment processes must definitely be implemented in point of environment and living organisms, many factories discharge their wastewaters to acceptor media without any treatment because of high costs. This study investigated zeolite and clay with high availability and low cost in wastewater treatment as more economically feasible alternatives to activated carbon. The wastewater treatment adequacy of zeolite-clay mixture was also investigated. We determined the optimum treatment time for heavy metal removal from the dye-containing wastewater samples as 6 hours. The mixture of clay+zeolite+activated carbon provided the highest removal of Cd, Cu, Mn, Pb, and Zn compared to zeolite, clay, activated carbon, activated carbon+clay, activated carbon+zeolite and clay+zeolite.

Comparative Study on the Effect of Common Ions on Zn2+ and Cu2+ Adsorption by Cattle Manure Vermicompost (VC) and VC-amended Soil

ABSTRACT Nowadays, special attention has been paid to remediate contaminated media through low-cost and high-efficiency biosorbents. In this research, the sorption of zinc (Zn2+) and copper (Cu2+) by cattle manure vermicompost (VC) and VC-amended soil and the effect of common ions on sorption was studied. The VC was characterized by using FT-IR spectra, SEM, BET analyses. Isotherm experiments were carried out with different concentrations of Zn2+ and Cu2+ (0–100 mg L−1) in the presence of 10 mM of background electrolytes (Ca2+, Mg2+, SO42-, and Cl−) as the binary system and the absence of other ions (single system). Data of Zn2+ and Cu2+ adsorption onto VC were fitted to the Langmuir equation. The maximum adsorption capacity (Qmax) of Zn2+ and Cu2+ onto VC in the single system was 7.27 and 17.73 mg g−1, respectively, which decreased in the following order Ca2+ > Mg2+ > SO42– > Cl – in the binary system. The effect of electrolytes on Zn2+ adsorption was more significant than Cu2+ and the Qmax of Zn2+ and Cu2+ decreased on average 20.4 and 10.8%, respectively. The VC addition increased adsorption in soil. Results indicate that VC had potential for the removal of Zn2+ and Cu2+ from single and binary systems.

Cellular Responses Induced by Zinc in Zebra Mussel Haemocytes. Loss of DNA Integrity as a Cellular Mechanism to Evaluate the Suitability of Nanocellulose-Based Materials in Nanoremediation.

Zinc environmental levels are increasing due to human activities, posing a threat to ecosystems and human health. Therefore, new tools able to remediate Zn contamination in freshwater are highly recommended. Specimens of Dreissena polymorpha (zebra mussel) were exposed for 48 h and 7 days to a wide range of ZnCl2 nominal concentrations (1–10–50–100 mg/L), including those environmentally relevant. Cellulose-based nanosponges (CNS) were also tested to assess their safety and suitability for Zn removal from freshwater. Zebra mussels were exposed to 50 mg/L ZnCl2 alone or incubated with 1.25 g/L of CNS (2 h) and then removed by filtration. The effect of Zn decontamination induced by CNS has been verified by the acute toxicity bioassay Microtox®. DNA primary damage was investigated by the Comet assay; micronuclei frequency and nuclear morphological alterations were assessed by Cytome assay in mussels’ haemocytes. The results confirmed the genotoxic effect of ZnCl2 in zebra mussel haemocytes at 48 h and 7-day exposure time. Zinc concentrations were measured in CNS, suggesting that cellulose-based nanosponges were able to remove Zn(II) by reducing its levels in exposure waters and soft tissues of D. polymorpha in agreement with the observed restoration of genetic damage exerted by zinc exposure alone.

Charcoal ash leachate and its sparingly soluble residue for acid mine drainage treatment: Waste for pollution remediation and dual resource recovery

Acid mine drainage (AMD) is one of the serious environmental pollutants due to its high acidity, toxic metals and sulfate concentration. In this study, Namibian hardwood charcoal ash leachate, sparingly soluble charcoal ash residue in deionized water and 25% NH4OH (aq.) solution were used for AMD treatment. The ICP-OES analysis results of treated AMD filtrate revealed that almost complete removal of Al, Co, Fe, Mn, Ni, Sb and Zn, and partial removal of Ca, Mg, and Na. The sulfate removal of charcoal ash leachate, residue and 25% NH4OH (aq.) was 66, 56 and 46%, respectively. The removal capacity of charcoal ash leachate and residue were almost better than 25% NH4OH (aq.). About 81% sludge composition recovered at pH 3.7 composed of Fe and O, while the sulfate recovered from the finally treated filtrate of AMD was with above 99% purity. This reveals the possibility of selective resource recovery with high purity from AMD using charcoal ash leachate. Furthermore, the formation of industrially important magnetic nanoparticles such as Fe3O4, Mg0.2Mn0.8Fe2O4 and Mg(Al, Fe)2O4 makes the sludge an eye-catching for future use. Indeed, waste for waste treatment for AMD pollution remediation and simultaneous double resource recovery are interesting findings of this study.

Optimization and mechanisms of methylene blue removal by foxtail millet shell from aqueous water and reuse in biosorption of Pb(II), Cd(II), Cu(II), and Zn(II) for secondary times

Foxtail millet shell as a raw efficient adsorbent was chosen first to eliminate methylene blue (MB) based on the uneven surface with many micropores, lots of negative charges, various functional groups, and some primary elements. And then the adsorbent-loaded MB was used to remove Pb(II), Cd(II), Cu(II), and Zn(II) from aqueous water for secondary adsorption. The effects of various factors were explored and optimized for removal rates of MB on the surface of the adsorbent using response surface methodology (RSM). After these factors were optimized, the confirmed removal rates of MB by the adsorbents were reached at 92.04, 93.05, and 93.36%, respectively from aqueous water while the solution pH was at 3, 7, and 11, respectively. The behavior of adsorption for MB dye was well-described by Langmuir isotherm (R 2 = 0.9951), demonstrating favorable monolayer adsorption of MB on the adsorbent with the maximum capacity of 165.07 mg·L−1 in aqueous water. The data of MB dye removal was better assessed by pseudo-second-order model (R 2 ≥ 0.9033), indicating an exchange of electrons has occurred between the adsorbent and MB particles, especially K and Ca ions of the adsorbent. In addition, the adsorbent-loaded MB has still presented better adsorption abilities for Pb(II), Cd(II), Cu(II), and Zn(II), respectively after MB removal in aqueous water. The adsorption mechanisms of adsorption were explored with the characterizations of the adsorbent before and after adsorption for the target pollutants by the methods of TEM, SEM, nitrogen physisorption isotherms, XPS, EDS, IR, and zeta potential classes. In summary, the results presented that the foxtail millet shell could be applied to remove MB dye effectively from aqueous water with the combined effects of electrostatic attraction, ion exchange, functional groups binding, and pore diffusion, but also, the adsorbent loaded with MB can be still applied to eliminate Pb(II), Cd(II), Cu(II), and Zn(II) by effects of electrostatic attraction and functional groups complexation in aqueous water. Novelty Statement In the present work, (a) the raw foxtail millet shell as a new potential adsorbent was used to remove MB dye from aqueous water for the first times, and operational variables of adsorption MB were investigated and optimized using response surface methodology, (b) the foxtail millet shell loaded MB as a disused adsorbent without any chemical reagent added was carried out to remove Pb(II), Cd(II), Cu(II), and Zn(II) ions, respectively in aqueous water for a secondary cycle, (c) adsorption mechanisms of MB removal on the adsorbent and the target heavy metals on the disused adsorbent were explored by the various analytical methods. This work provides evidence for the adsorption of MB on the natural adsorbent and improves the utilization efficiency of the used adsorbent on Pb(II), Cd(II), Cu(II), and Zn(II) removal in aqueous water.

Removal of Ni (II), Mn (II) and Zn (II) from crude yellow cake aqueous solution by cross-linked chitosan and polyvinyl alcohol

The removal of Ni (II), Mn (II) and Zn (II) from crude yellow cake onto chitosan cross-linked by Epichlorohydrin (CS-ECH) and polyvinyl alcohol (PVA) were investigated in nitrate solutions. The influence of contact time, pH, temperature and initial metal concentrations on the adsorption processes were investigated using batch modes. Langmuir and Fruindlish models were used for investigation of adsorption isotherm. The results showed that the equilibrium adsorption behavior of metal ions onto CS-ECH and PVA could be fitted to Langmuir model. The total maximum adsorption capacity of CS-ECH and PVA were calculated, and the results indicate the higher values of CS-ECH than PVA, due to the properties of chemical structure of CS-ECH. The adsorption kinetics parameters were also tested using pseudo-first-order, pseudo-second-order models, and interparticle diffusion models. The results indicate the adsorption processes of metal ions on both CS-ECH and PVA followed the pseudo-first-order and the pseudo-second-order models which meaning the mixed adsorption, except the adsorption of Mn (II) on PVA is only described by the pseudo-second-order equation. The results indicate the adsorption processes of metal ions followed the pseudo-second-order models for both CS-ECH and PVA. Otherwise, the values of thermodynamic parameters (ΔHoads, ΔSoads, and ΔGoads) of metal ions removal by CS-ECH and PVA exhibit the spontaneity, and exothermicity of adsorption processes.

Competitive sorption of Cd, Cr, Cu, Ni, Pb and Zn from stormwater runoff by five low-cost sorbents; Effects of co-contaminants, humic acid, salinity and pH

For a comprehensive estimation of metals removal by sorbents in stormwater systems, it is essential to evaluate the impacts of co-contaminants. However, most studies consider only metals (single or multiple), which may overestimate performance. This study employed a batch method to investigate the performance of five low-cost sorbents – coconut coir fiber (CCF), blast furnace slag (BFS), waste tire crumb rubber (WTCR), biochar (BC), and iron coated biochar (FeBC) – for simultaneous removal of Cd, Cr, Cu, Ni, Pb and Zn from simulated stormwater (SSW) containing other contaminants (nutrients and polycyclic aromatic hydrocarbons). BFS and CCF demonstrated the highest sorption capacity of all metals (> 95% removal) in all systems (single and multi-contaminant). However, the presence of other contaminants in solution reduced metals removal for other sorbents, as follows (highest to lowest removal): single-metal > multi-metal > multi-contaminant solutions, and removal efficiency ranking among metals was generally Cr~Cu~Pb > Ni > Cd > Zn. Humic acid (HA) negatively affected the metal sorption, likely due to the formation of soluble HA-metal complexes; NaCl concentration did not impact removal, but alkaline pH improved removal. These findings indicate that sorbents need to be tested under realistic stormwater solution chemistry including co-contaminants to appropriately characterize performance prior to implementation.

Solvent extraction-based recovery of Co from leach solutions of Cu[sbnd]Co ores using a Mextral 6103H-naphthenic acid- isooctanol system

A Mextral 6103H–naphthenic acid–isooctanol synergistic extraction system was used for the selective separation of Co from pre-treated leach solutions of CuCo ores and the extraction performance, the extraction/stripping kinetics, and the phase separation properties of this system were determined. At pH 4.0, Co was selectively extracted from the feed solution containing Co, Ni, Zn, Mg, Mn, and Ca. The Co-loaded organic phase was easily stripped with a solution containing Co (100 g/L) and H2SO4 (40 g/L) at an O/A ratio of 5:1 and 25oC. Based on the McCabe-Thiele plots for Co extraction, scrubbing and stripping, tests involving simulated batch counter-current extraction (two stages), scrubbing (two stages) and stripping (two stages) were performed. A Co extraction efficiency of 99.7% (over two extraction stages) was obtained, while nearly all Mg, Mn, and Ca remained in the raffinate. The two-stage scrubbing of the co-extracted loaded organics resulted in the efficient removal of Zn (88.3%), Mn (95.2%), Mg (94.0%), and Ca (92.0%). The two-stage stripping of Co had an efficiency of 99.1%. The stripping liquor contained low levels of Zn (3.4 mg/L), Ni (0.2 mg/L), Mn (2.4 mg/L), Mg (1.2 mg/L) and Ca (0.8 mg/L), with the resulting Co purity equaling 99.98%. Thus, the developed process holds great promise for the selective recovery of Co from the leach solutions of CuCo ores containing multiple metals

Purification Performance of Filtration Process for Pig Slurry Using Marine Sands, Silty Loam Soils, Fly Ash and Zeolite

Filtration is a simple ecological process for the treatment of effluents. This research examined the physicochemical properties of micronutrients, macronutrients, and heavy metals (HM) removed after the slow filtration of pig slurry (PS) through multiple media: sands, silt loam soils, fly ash, and zeolite. The objective was to find a new layer that can be added to our constructed wetland (CW) to improve its efficiency and study how the slurry reacts to these natural materials. The filtration achieved an approximate removal rate of 99.99% for total suspended solids (TSS) and nitrogen and 61, 94, 72, and 97%, respectively, for electrical conductivity (EC), turbidity, chemical oxygen demand (COD), and five-day biological oxygen demand (BOD5). The two sands, soil 1, and zeolite, had a macronutrient reduction median of 60%, whereas soil 2, 3, 4, and fly ash released macronutrients such as Na, Ca, and Mg. All the media achieved nearly 99.99% micronutrient removal for Fe and Zn. The Cu removal rate was over 86% except for sand 1 and 2 and soil 1, which reduced it to only 46%; the overall Mn removal rate was more than 80% except for soil 3 and soil 4, where it was only 9%. Zeolite had a 99.99% removal capacity for HM as opposed to sand 2, soil 4, and fly ash, which released some HMs (Ni, Cu). This inexpensive and abundant media filtration process is sound technically and financially sound and seems to be an ideal cost-efficient treatment for pig slurry.

Application of radiotracer technique in remediation of Zn(II) from aqueous solutions by dry cowdung powder

Heavy metal pollution is caused due to anthropogenic activities and is considered as a serious environmental problem which endangers human health and environment. The present study deals with biosorption, an eco-friendly technique for the removal of heavy metal Zn(II) from aqueous medium. Various natural materials have been explored for the uptake of metal ions, where most of them are physically or chemically enhanced. Dry cowdung powder (DCP) has been utilized as a low-cost, environmentally friendly humiresin without any pre-treatment, thus demonstrating the concept of Green Chemistry. Batch biosorption studies using 65Zn(II) tracer were performed and the impact of different experimental parameters was studied. Results revealed that at pH 6, 94 ± 2% of Zn(II) was effectively biosorbed in 5 min, at 303 K. The process was spontaneous and exothermic, following pseudo-second-order reaction. The mechanism of heavy metal biosorption employing green adsorbent was therefore elucidated in order to determine the optimal method for removing Zn(II) ions. DCP has a lot of potential in the wastewater treatment industry, as seen by its ability to meet 3A's affordability, adaptability, and acceptability criteria. As a result, DCP emerges as one of the most promising challengers for green chemistry and the zero-waste idea.

Simultaneous removal of heavy metals and bioelectricity generation in microbial fuel cell coupled with constructed wetland: an optimization study on substrate and plant types.

A microbial fuel cell coupled with constructed wetland (CW-MFC) was built to remove heavy metals (Zn and Ni) from sludge. The performance for the effects of substrates (granular activated carbon (GAC), ceramsite) and plants (Iris pseudacorus, water hyacinth) towards the heavy metal treatment as well as electricity generation was systematically investigated to determine the optimal constructions of CW-MFCs. The CW-MFC systems possessed higher Zn and Ni removal efficiencies as compared to CW. The maximal removal rates of Zn (76.88%) and Ni (66.02%) were obtained in system CW-MFC based on GAC and water hyacinth (GAC- and WH-CW-MFC). Correspondingly, the system produced the maximum voltage of 534.30 mV and power density of 70.86 mW·m-3, respectively. Plant roots and electrodes contributed supremely to the removal of heavy metals, especially for GAC- and WH-CW-MFC systems. The coincident enrichment rates of Zn and Ni reached 21.10% and 26.04% for plant roots and 14.48% and 16.50% for electrodes, respectively. A majority of the heavy metals on the sludge surface were confirmed as Zn and Ni. Furthermore, the high-valence Zn and Ni were effectively reduced to low-valence or elemental metals. This study provides a theoretical guidance for the optimal construction of CW-MFC and the resource utilization of sludge containing heavy metals.

Changes in Adsorption Characteristics of Heavy Metals and Organic Pollutants Following Pyrolytic Treatment of Petroleum-Contaminated Dredged Sediment

Objectives : This study investigated the changes in adsorption characteristics of dredged sediment for heavy metals and organic pollutants after petroleum contamination followed by pyrolytic treatment.Methods : Pyrolytic treatment was conducted at two heating temperatures, 300℃ and 500℃, for 30 min using muffle furnace. Sediment spiked with No. 6 Fuel Oil at initial total petroleum hydrocarbon (TPH) concentrations of 5,000-50,000 mg/kg was used. Sorption experiments were conducted for heavy metals (Cd, Cu, Pb, Zn, Ni, Hg, As, Cr), phenanthrene and bisphenol A using clean sediment (sediment before the petroleum spiking) and pyrolyzed sediment.Results and Discussion : Pyrolytic treatment at 500℃ showed excellent TPH removal efficiency, resulting in the residual concentration of less than 50 mg/kg for all initial TPH contamination levels. High efficiencies (> 98%) were observed for the sorptive removal of Cu, Zn and Pb in the aqueous phase for both the two sediments. The removal efficiencies of Ni and Cd from the aqueous phase using pyrolyzed sediment were 31% and 24% lower than those using clean sediment, respectively, due to the reduced oxygen-containing functional group content and specific surface area after the pyrolytic treatment. The sediment-water distribution coefficient (Kd) and sediment organic carbon-water distribution coefficient (Koc) values of bisphenol A and phenanthrene in pyrolyzed sediment were considerably higher than in clean sediment due to the high organic compound sorption affinity exhibited by carbonaceous matter that was generated during the pyrolytic sediment treatment.Conclusions : The capability of pyrolytic treatment of dredged sediment to notably improve its organic compound sorption capacity may be exploited for beneficial use of the treatment product. The product may be applied as fill and backfill, soil amendment, or in-situ sediment capping materials in highly industrialized areas where mitigation measures for organic contaminant migration are necessary.

Removal of metal ions using a new magnetic chitosan nano-bio-adsorbent; A powerful approach in water treatment

In this study, a magnetic chitosan/Al2O3/Fe3O4 (M-Cs) nanocomposite was developed by ethylenediaminetetraacetic acid (EDTA) functionalization to enhance its adsorption behavior for the removal of Cd(II), Cu(II) and Zn(II) metal ions from aqueous solution. The results revealed that the EDTA functionalization of M-Cs increased its adsorption capacity ~9.1, ~5.6 and ~14.3 times toward Cu, Cd and Zn ions. The maximum adsorption capacity followed the order of Cd(II) > Cu(II) > Zn(II) and the maximum adsorption efficiency was achieved at pH of 5.3 with the removal percentage of 99.98, 93.69 and 83.81 %, respectively, for the removal of Cu, Cd and Zn ions. The metal ions adsorption kinetic obeyed pseudo-second-order equation and the Langmuir isothermal was found the most fitted model for their adsorption isothermal experimental data. In addition, the thermodynamic study illustrated that the adsorption process was exothermic and spontaneous in nature.

Removal behavior and chemical speciation distributions of heavy metals in sewage sludge during bioleaching and combined bioleaching/Fenton-like processes

The removal and chemical speciation changes of heavy metals in the sewage sludge during the single bioleaching and combined bioleaching/Fenton-like processes were compared in this study. The improvement in the dewaterability of the treated sludge was also investigated. The single bioleaching led to a removal of Zn, Cu, Cd, Cr, Mn, Ni, As and Pb of 67.28%, 50.78%, 64.86%, 6.32%, 56.15%, 49.83%, 20.78% and 10.52% in 10 days, respectively. The chemical speciation analysis showed that the solubilization of heavy metals in mobile forms (exchangeable/acid soluble and reducible forms) and oxidizable form was the main reason for their removal. Subsequent Fenton-like treatment was carried out at different bioleaching stages when the bioleached sludge dropped to certain pH values (4.5, 4.0 and 3.0), by adding H2O2 at different dosages. The highest removal ratio of Zn, Cu, Cd, Cr, Mn and Ni could reach 75.53%, 52.17%, 71.91%, 11.63%, 66.29% and 65.19% after combined bioleaching/Fenton-like process, respectively, with appropriate pH and H2O2 dosages in less than 6 days. The solubilization efficiencies of these heavy metals in mobile forms were further improved by Fenton-like treatment. The removal efficiencies of As and Pb decreased due to their transformation into insoluble forms (mostly residual fraction) after Fenton treatment. The capillary suction times (CST) of the raw sludge (98.7 s) decreased by 79.43% after bioleaching and 87.44% after combined process, respectively.

Fabrication of Nanoporous Al by Vapor-Phase Dealloying: Morphology Features, Mechanical Properties and Model Predictions

The physical and chemical properties shown by nanoporous metals, related to their unique structure, make them very promising for application in several fields. Recently, vapor-phase dealloying has been reported as a method for the preparation of several non-noble nanoporous metals, alternatively to dealloying in aqueous solutions. Using this approach, we have successfully fabricated nanoporous Al starting from an Al20Zn80 nanocomposite obtained by ball milling. The nanocomposite was annealed at 550 °C under high-vacuum conditions, and the difference in the vapor pressures allowed the selective removal of Zn by vapor-phase dealloying. The morphology of the resulting nanoporous material was analyzed by Scanning Electron Microscopy showing pores from few to thousands of nm; moreover, the nanoporous 3D structure was observed through Serial Block Face-Scanning Electron Microscopy. A specific surface area as high as 73 m2 g−1 was estimated by N2 physisorption measurements. In addition, a fractal model able to well reproduce the morphology of nanoporous Al was built. This model has been used for predicting mechanical properties which are in good agreement with experimental data obtained by nanoindentation.

Removal of Zn(II) and Ni(II) heavy metal ions by new alginic acid-ester derivatives materials

The present work concerns the preparation of new materials based on alginic acid (AA) and diols in a facile and efficient process by improving the adsorption properties of Zn(II) and Ni(II) metal ions on the modified AA. The materials were analysed by zeta potential, thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), in addition to the Fourier Transform InfraRed spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) before and after the adsorption behaviour was conducted. The results show that the esterification of AA with diols of different lengths significantly improves its adsorption efficiency of Zn(II) and Ni(II) with Qmax up to 200 mg/g and 185.185 mg/g respectively. Equilibrium and kinetic studies showed that the Langmuir and Freundlich adsorption isotherm models fit the experimental data well, and followed a pseudo-first order kinetic model and the particle diffusion model with correlation coefficients R2 ≈ 1.

Removal effects of different emergent-aquatic-plant groups on Cu, Zn, and Cd compound pollution from simulated swine wastewater

Aquatic plants play effective in removing heavy metal (HM) as a prominent factor of bioremediations, however, there are still knowledge gaps in species selection and configuration for high removal efficiency (RE) of compound HM and ornamental value. In this study, seven emergent-aquatic-plant species were configured into seven groups and planted in a simulated swine wastewater (SW) with Cu, Zn, and Cd for 75 days in summer. REs of Cu, Zn, and Cd were 45.06–86.93%, 42.40–87.22%, and 73.85–85.52% at day 75, respectively. Higher REs were observed from day 30–45 for Cu and Zn, whereas days 15–30 for Cd. The synergistic removal of Zn and Cu or Zn and Cd was almost observed (p < 0.05). The configuration of G5 (S. tabernaemontani, I. sibirica, and P. cordata) was generally efficient roles in the removal at day 45, with REs of 85.14%, 87.06%, and 83.56% for Cu, Zn, and Cd, respectively. The dry weight of roots, water NH4+-N, temperature, pH, and dissolved oxygen acted on heavy-metal removal. During days 45–75, concentrations of Cu, Zn, and Cd in G5 were 0.52–0.66, 0.54–0.65, and 0.23–0.33 mg L−1. The former two were below the limits of Grade Ⅱ (1.0 mg L−1) and the latter was above the limits of Grade Ⅴ (0.1 mg L−1; GB3838-2002). Thus, G5 could be optimal for Cu and Zn removal from simulated SW, however, efficient Cd removal is required to ensure efficient SW recycling.