Efficiency Of Cu Research Articles

Study on Cu- and Pb-contaminated loess remediation using electrokinetic technology coupled with biological permeable reactive barrier

Although the electrokinetic (EK) remediation has drawn great attention because of its good maneuverability, the focusing phenomenon near the cathode and low removal efficiency remain to be addressed. In this study, a novel EK reactor was proposed to remediate Cu and Pb contaminated loess where a biological permeable reactive barrier (bio-PRB) was deployed to the middle of the EK reactor. For comparison, three test configurations, namely, CG, TG-1, and TG-2, were available. CG considered the multiple enzyme-induced carbonate precipitation (EICP) treatments, while TG-1 considered both the multiple EICP treatments and pH regulation. TG-2 further considered NH4+ recovery based on TG-1. CG not only improved Cu and Pb removals by the bio-PRB but also depressed the focusing phenomenon. TG-1 causes more Cu2+ and Pb2+ to migrate toward the bio-PRB and aggravates Cu and Pb removals by the bio-PRB, depressing the focusing phenomenon. TG-2 depressed the focusing phenomenon the most because Cu2+ and Pb2+ can combine with not only CO32− but PO43−. The removal efficiency of Cu and Pb is 34% and 36%, respectively. A NH4+ recovery of about 100% is attained.

Selective solvent extraction of Cu(II) from aqueous solutions using an acyl-based thiourea: Extraction study and DFT analysis of reaction mechanism

Currently, copper-containing wastewater poses a great threat to the surrounding living areas due to its toxic and non-biodegradable properties. The solvent extraction technique for removing copper(II) from wastewater has been identified as a straightforward and effective method. In this study, novel acyl-containing thiourea extractants, namely N-benzoyl-N′,N′-diethyl thiourea (BDETU), N-benzoyl-N′,N′-dibutyl thiourea (BDBTU) and N-benzoyl-N′-butyl thiourea (BBTU), were prepared and employed as extractants for the efficient removal of Cu(II) ions from aqueous solution. Experimental results indicated that the highest extraction efficiency of Cu(II) by BDETU was 99.4% under the optimal extraction conditions, which surpassed the performance of both BDBTU and BBTU. The reusability and selectivity experiments further confirmed the enduring high extraction efficiency of BDETU over 8 consecutive extraction-stripping cycles. These findings suggest that BDETU exhibits promising prospects for wide-ranging applications owing to its excellent extraction stability and selectivity. The investigation into the extraction mechanism of Cu(II) with acyl thiourea molecule revealed that one mole of Cu(II) was extracted with two moles of extractants through the formation of Cu-O-C and Cu-S-C bonds.

Influence of LiNO3 on the Lithium Metal Deposition Behavior in Carbonate-Based Liquid Electrolytes and on the Electrochemical Performance in Zero-Excess Lithium Metal Batteries.

Continuous lithium (Li) depletion shadows the increase in energy density and safety properties promised by zero-excess lithium metal batteries (ZELMBs). Guiding the Li deposits toward more homogeneous and denser lithium morphology results in improved electrochemical performance. Herein, a lithium nitrate (LiNO3 ) enriched separator that improves the morphology of the Li deposits and facilitates the formation of an inorganic-rich solid-electrolyte interphase (SEI) resulting in an extended cycle life in Li||Li-cells as well as an increase of the Coulombic efficiency in Cu||Li-cells is reported. Using a LiNi0.6 Co0.2 Mn0.2 O2 positive electrode in NCM622||Cu-cells, a carbonate-based electrolyte, and a LiNO3 enriched separator, an extension of the cycle life by more than 50 cycles with a moderate capacity fading compared to the unmodified separator is obtained. The relative constant level of LiNO3 in the electrolyte, maintained by the LiNO3 enriched separator throughout the cycling process stems at the origin of the improved performance. Ion chromatography measurements carried out at different cycles support the proposed mechanism of a slow and constant release of LiNO3 from the separator. The results indicate that the strategy of using a LiNO3 enriched separator instead of LiNO3 as a sacrificial electrolyte additive can improve the performance of ZELMBs further by maintaining a compact and thus stable SEI layer on Li deposits.

Effect of different production methods on physicochemical properties and adsorption capacities of biochar from sewage sludge and kitchen waste: Mechanism and correlation analysis

Different pyrolysis methods, parameters and feedstocks result in biochars with different properties, structures and removal capacities for heavy metals. However, the role of each property on adsorption capacity and corresponding causal relationships remain unclear. Here, we investigated various physicochemical properties of biochar produced via three different methods and two different feedstocks to clarify influences of biomass sources and pyrolysis processes on biochar properties and its heavy metal adsorption performance. Experimental results showed biochars were more aromatic and contained more functional groups after hydrothermal carbonization, while they had developed pores and higher surface areas produced by anaerobic pyrolysis. The inclusion of oxygen resulted in more complete carbonization and higher CEC biochar. Different biochar properties resulted in different adsorption capacities. Biochar produced by aerobic calcination showed higher adsorption efficiency for Cu and Pb. Correlation analysis proved that pH, cation exchange capacity and degree of carbonization positively affected adsorption, while organic matter content and aromaticity were unfavorable for adsorption. Microstructure and components determined biochar macroscopic properties and ultimate adsorption efficiency for metal ions. This study identifies the degree of correlation and pathways of each property on adsorption, which provides guidance for targeted modification of biochar to enhance its performance in heavy metal removal.

The utilization of cost-effective natural sorbents for the eradication of heavy metal contaminants from the real world-based adsorbate system

In India, Industrial growth has resulted towards the release of numerous contaminated heavy metals into the environment, Various industries directly discharged the effluents containing harmful pollutants such as toxic heavy metals into the aqueous medium. There are numbers of treatment methods available to remove toxic elements from effluents before disposal. Several research investigations have been conducted to determine the capacity of unconventional absorbents to remove various wastewater impurities. Bio-sorption technique uses agricultural and natural left-over materials as adsorbents since they remain considerably less expensive, supportable, and available than traditional effluent treatment technologies. This study concentrates removal efficiency of orange peels (OP), rice husk (RH) and sugarcane bagasse (SCB) from the industrial effluents. Adsorption studies have been conducted for OP, RH and SCB with differing dose, pH, and contact duration, determined to be appropriate and leading to the highest levels of removal effectiveness. At 1.00 gm dosage, the maximum % removal efficiency of Cu, Cr, Ni, Cd and Zn removal for OP, RH and SCB were 84.90%, 90.45%, 86.21%, 98.00% and 74.11% respectively by using OP, RH and SCB the max. percentage removal efficiency of Cu, Cr, Ni, Cd and Zn for OP, RH were 82.81%, 76.80%, 76.16%, 78.46%, 78.59% at a pH value of 5, 6, 5, 7 and 7 respectively. The max. percentage removal efficiency of Cu, Cr, Ni, Cd and Zn using OP, RH and SCB were 93.45%, 93.05%,77.66%, 94.62%, 85.10% at the contact time of 120, 60, 120, 60 and 80 minutes respectively.

Nano-impregnation on metakaolin backbone for enhanced removal of Cu(II) and Mn(II) ions in a binary system using fixed bed column

This paper presents a comprehensive study on the synthesis and characterization of a novel composite material composed of metakaolin (MK), cellulose nanofibers (CNF), graphene oxide (GO), and zinc oxide (ZnO) for the efficient removal of heavy metals from wastewater. The main objective of this research was to enhance the removal efficiency of Cu(II) and Mn(II) ions in a binary system using a fixed bed column adsorption technique while investigating the effect of impregnating the nanomaterials. The synthesized samples were subjected to a thorough characterization using various techniques. These analyses provided insights into the structural properties and morphology of the composite material. The adsorption performance of the MK/CNF/GO/ZnO composite was evaluated through breakthrough curve analysis and kinetic modeling. The MDR model provided good fits with R2 values of 0.962 and 0.967 for Cu(II) and Mn(II) respectively. Based on the experimental breakthrough curve data, the saturation and breakthrough capacities of the composite material were calculated to be 5.97 mg/g and 4.84 mg/g for Cu(II) and Mn(II) respectively, achieved after a saturation time of 102 min for Cu(II) and 128 min for Mn(II). The results demonstrated a synergistic effect between GO and CNF, resulting in enhanced adsorption efficiency. The incorporation of ZnO nanoparticles further improved the adsorption capacity due to their high surface area, providing additional active sites for adsorption. The results showed that combining CNF, GO, and ZnO in a composite resulted in extended breakthrough and exhaustion times compared to the combination of CNF and GO alone.

Synergistic effect and mechanism of zero-valent iron activated persulfate on Cu(II)–EDTA decomplexation enhanced with weak magnetic field

Herein, a weak magnetic field (WMF) was applied to improve the catalytic degradation of the copper-ethylene diamine tetraacetic acid complex (Cu(II)–EDTA) and recovery of Cu using zero-valent iron/peroxomonsulfate (ZVI/PS). The removal rates of Cu(II)–EDTA in the WMF/ZVI/PS system were 7.92 and 1.33 times those in the ZVI and ZVI/PS systems, respectively. The recovery rates of Cu in the WMF/ZVI/PS system were 4.78 and 1.25 times more than those in ZVI and ZVI/PS systems, respectively. Scavenger quenching experiments and electron spin resonance (ESR) results showed that more active radicals (SO4•− and •OH) were produced and both SO4•− and •OH played the important role in Cu(II)–EDTA degradation in the WMF/ZVI/PS system. The ZVI and PS dosages and initial solution pH considerably affected the removal efficiency of Cu(II)–EDTA. X-ray energy-dispersive spectroscopy (EDS) results showed that WMFs could accelerate the enrichment of paramagnetic Cu2+ on the ZVI surface. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results showed that Cu2+ ions were first adsorbed on the corroded ZVI and then reduced to Cu0 with time. A possible Cu(II)–EDTA decomposition and Cu reduction mechanism was also proposed. This study provides a promising and ecofriendly technique for treating industrial wastewater containing organic complexed metals.

Extraction methods optimization of available heavy metals and the health risk assessment of the suburb soil in China.

Heavy metal pollution has attracted increasing concern due to its high toxicity and persistence. A suitable extraction procedure for available heavy metals in soil is necessary for assessing the ecological risk. In this work, the single extraction methods aided by shaking and microwaves were investigated and analyzed for their ability to extract available heavy metals from soil samples, and a total of 42 soil samples were collected from suburbs of Zhengzhou city in China. The extraction efficiency of Cu, Zn, As, and Cd in the certified fluvo-aquic soil was compared using eight different types of solutions: CaCl2, CH3COONH4, NH4NO3, CH3COOH, Na2EDTA, DTPA, HNO3, and NH4H2PO4. Results indicated that the shaking-assisted method that utilized Na2EDTA as an extractant demonstrated satisfactory efficiency and was chosen for further optimization and that the optimal conditions were obtained using 0.05M Na2EDTA at pH 7, soil-liquid ratio 1:20, and extraction duration 2h, which gained the perfect extraction efficiency ranging from 85.8 to 109.5%. The proposed approach has been applied to extract available Cu, Zn, As, and Cd in soils of Zhengzhou suburbs, where the mean values varied from 0.129 to 6.881mg/kg. The bioavailability of different heavy metals in the soil varies greatly, with Cd having the highest activity in the survey region. Significant (p < 0.01) positive relationships were observed between the available state and the total amount of all the heavy metals. The assessment of health risks associated with heavy metals indicated that there was no risk for chronic non-carcinogenic effects. Even though the total amount of metal elements in suburban soil of Zhengzhou is 1.6% with high carcinogenic risk, the risk of available elements is still within the acceptable range, which verified that the risk grade obtained by the total amount is higher than the actual risk.

Antibiotic and Heavy Metal Co-Resistant Strain Isolated from Enrichment Culture of Marine Sediments, with Potential for Environmental Bioremediation Applications.

Antibiotics and heavy metals have caused serious contamination of the environment and even resulted in public health concerns. It has therefore become even more urgent to adopt a sustainable approach to combating these polluted environments. In this paper, we investigated the microbial community of marine sediment samples after 255 days of enrichment culture under Cu (II) and lincomycin stress and ZC255 was the most resistant strain obtained. The 16S rRNA gene sequence confirmed that it belonged to the genus Rossellomorea. Strain ZC255 was resistant to 12 kinds of antibiotics, and had a superior tolerance to Cu (II), Pb (II), Ni (II), Zn (II), Cr (III), and Cd (II). Moreover, it exhibits strong bioremoval ability of Cu and lincomycin. The removal efficiency of Cu (II) and lincomycin can achieve 651 mg/g biomass and 32.5 mg/g biomass, respectively. Strain ZC255 was a promising isolate for pollution bioremediation applications.

Evaluation of efficiency of Wheat straw nanocellulose as nanoadsorbent for the removal of divalent copper, lead and zinc from aqueous solution

Novel nanocellulose (cellulosic carbohydrate polymer) embedded with Wheat straw was synthesized, characterized and examined as nanoadsorbent for the removal of copper, lead and zinc metals from aqueous solution through batch mode. The effects of pH, dose, contact time, temperature and synchronous cations on the amount of Cu (II), Pb (II) and Zn (II) adsorbed have been probed. The desirable pH was 8 and nanoadsorbent dose was 0.6 g/50 mL in the adsorption study. The removal efficiencies of Cu (II), Pb (II) and Zn (II) were 88.75%, 81.18%, 86.84% respectively. Adsorption kinetic study was employed to analyze experimental data and adsorption process followed pseudo second order kinetic model. Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models were used to indicate the adsorption of Cu (II), Pb (II) and Zn (II) on WSN and thermodynamic study affirmed that adsorption process was endothermic and spontaneous. AFM indicated size and morphology and attachment of functional groups on WSN were examined by FTIR. The results confided that adsorption is economically competent method for removing Cu (II), Pb (II) and Zn (II) and WSN is anticipative owing to its ease and low cost of regeneration

Assessment of the Stabilization of Cu-, Pb-, and Zn-Contaminated Fine Soil Using Cockle Shells, Scallop Shells, and Starfish

Soil washing is a well-established remediation technology for treating soil contaminated with heavy metals. It involves the separation of contaminants from the soil using acidic washing agents. Nevertheless, the application of washing agents at high concentrations may lead to soil acidification and the destruction of the clay structure. To avert this problem, recently, a soil washing variant has been presented, which solely employs high-pressure water without any chemical solvents. However, the fine soil generated from soil washing at a high-pressure contains high levels of heavy metals and requires proper treatment. This study examines the use and applicability of natural aquaculture materials as stabilizing agents for treating heavy metals (Cu, Pb, and Zn) in fine soil generated by high-pressure soil washing. Three aquaculture materials were assessed, namely, cockle shells (CKS), scallop shells (SLS), and Asterias amurensis starfish (ASF). Each material was processed to yield three types of stabilizing agents: natural type (-#10 mesh), natural type (-#20 mesh), and calcined(C) type (-#10 mesh). Each stabilizing agent was added to the contaminated soil at a ratio of 0 to 10 wt%, and then, mixed with an appropriate amount of water. After wet curing for 28 days, the stabilization efficiency of Cu, Pb, and Zn was evaluated using 0.1 N HCl solution. The elution of heavy metals showed a decreasing trend with higher dosages of stabilizing agents. The calcined type (-#10) showed the highest stabilization efficiency, followed by the natural type (-#20) and natural type (-#10). In addition, a comparison of the efficiency of the different stabilizing agents showed that calcined ASF (CASF) had the highest stabilization efficiency, followed by calcined SLS (CSLS), calcined CKS (CCKS), natural ASF (NASF), natural SLS (NSLS), and natural CKS. Finally, analysis of samples exhibiting the highest stabilization efficiency by scanning electron microscopy–energy dispersive X-ray spectrometry (SEM–EDX) confirmed that the pozzolanic reaction contributed to the stabilization treatment. The results of this study demonstrate that heavy metal-contaminated fine soil, generated by high-pressure washing, can be remediated by stabilizing Cu, Pb, and Zn using waste aquaculture materials (CKS, SLS, and ASF), which are often illegally dumped into the sea or landfills and cause environmental damage.

Resource utilization of ultrasonic carbonated MSWI fly ash as cement aggregates: Compressive strength, heavy metal immobilization, and environmental-economic analysis

Ultrasonic carbonation technology is effective for municipal solid waste incineration fly ash (MSWI FA) pretreatment. However, the subsequent disposal route is unclear. In this study, the mechanical strength and heavy metal immobilization effects of raw FA (RFA), washed FA (WFA), conventional carbonated FA (CFA), and ultrasonic carbonated FA (UFA) as cement aggregates in the preparation of concrete were investigated in comparison. The reaction kinetic analysis showed that ultrasonic excitation promoted the internal diffusion phase of the carbonation reaction. The compressive strength of the 28-day solidified bodies was in the order of UFA (32.2 MPa) > CFA (22.8 MPa) > WFA (16.4 MPa) > RFA (12.6 MPa). The 3-day UFA solidified body showed the highest degree of hydration and polymerization through 29Si solid-nuclear-magnetic analysis. The nano-CaCO3 in the UFA provided more nucleation sites and hydration reaction sites for the hydration reaction. In addition, the fine UFA particles filled the pores between cement particles, enhancing the strength of the product. Heavy metal leaching tests described that CFA and UFA met the criteria for resource utilization (HJ/T 1134–2020), and the immobilization efficiency of Cu, Pb, and Zn in the UFA solidified body was above 95.6%, 99.3%, and 99.2%, respectively, mainly by the dual immobilization of carbonate chemical precipitation and cement hydration. Considering 11 environmental impact factors and economic benefits, life-cycle-assessment and cost-benefit analysis were selected. The integrated environmental-economic results show that cement usage is the main influencing factor. UFA scenario was recommended as engineering applications with low global warming potential.

An efficient and affordable hydrometallurgical process for co-treatment of copper smelting dust and arsenic sulfide residue

We developed a novel method for comprehensive treatment of copper smelting dust (CSD) and arsenic sulfide residue (ASR) using three processes: leaching CSD by sulfuric acid, Cu precipitation with ASR, and FeSO4·7H2O/O2 co-oxidizing and precipitating As. The novel method not only realizes the recovery of valuable metals from dust, but also removes and solidifies As in CSD and ASR in the form of scorodite to achieve harmless treatment. With sulfuric acid as leaching agent, the leaching efficiencies of Cu, Zn and As reached 87.23%, 93.07% and 95.21%, respectively, under the optimum conditions. Subsequently, Cu in CSD leaching solution was precipitated in the form of CuS by ASR, and the Cu precipitation percentage reached 97.39% and 94.86 wt. % of As in ASR entered the solution under the optimum conditions. Finally, FeSO4·7H2O/O2 was used to co-oxidize As(III) and simultaneously precipitate the As in the form of scorodite. The oxidation percentage and precipitation percentage of arsenic reached 98.73% and 96.77%, respectively. The leaching concentration of As in the arsenic precipitate residue (APR) was only 0.17 mg/L in the toxicity characteristic leaching procedure (TCLP). The arsenic precipitate solution can be directly used to recover Zn.

Synchronous decomplexation and mineralization of copper complexes by activating peroxymonosulfate with magnetic bimetallic biochar derived from municipal sludge

Efficient removal of copper complexes is a challenging issue due to their robust stability and solubility. In this study, CoFe2O4–Co0 loaded sludge-derived biochar (MSBC), a magnetic heterogeneous catalyst, was prepared to activate peroxymonosulfate (PMS) for the decomplexation and mineralization of some typical copper complexes (including Cu(Ⅱ)-EDTA, Cu(Ⅱ)-NTA, Cu(Ⅱ)-citrate, and Cu(Ⅱ)-tartrate). The results showed that abundant cobalt ferrite and cobalt nanoparticles were decorated in the plate-like carbonaceous matrix, making it a higher degree of graphitization, better conductivity and more excellent catalytic activity than the raw biochar. Cu(Ⅱ)-EDTA was chosen as the representative copper complex. Under the optimum condition, the decomplexation and mineralization efficiency of Cu(Ⅱ)-EDTA in MSBC/PMS system were 98% and 68% within 20 min, respectively. The mechanistic investigation confirmed that the activation of PMS by MSBC followed both a radical pathway contributed by SO4•− and •OH and a nonradical pathway contributed by 1O2. In addition, the electron transfer pathway between Cu(Ⅱ)-EDTA and PMS facilitated the decomplexation of Cu(Ⅱ)-EDTA. Jointly, CO, Co0, and the redox cycles of Co(Ⅲ)/Co(Ⅱ) and Fe (Ⅲ)/Fe (Ⅱ) were found to play a critical role in the decomplexation process. Overall, the MSBC/PMS system provides a new strategy for efficient decomplexation and mineralization of copper complexes.

Stability of Cu(InxGa1−x)Se2 Solar Cells Utilizing RbF Postdeposition Treatment under a Sulfur Atmosphere

Alkali halide postdeposition treatments (PDTs) have become a key tool to maximize efficiency in Cu(InxGa1−x)Se2 (CIGS) photovoltaics. RbF PDTs have emerged as an alternative to the more common Na‐ and K‐based techniques. This study utilizes temperature‐dependent current–voltage (JVT) measurements to study a unique RbF PDT performed in a S atmosphere. The samples are measured before and after 6 months in a desiccator to study device stability. Both samples contain Na and K which diffuse from the soda–lime glass substrate. A reference sample and a RbF + S PDT sample both show the development of a rear contact barrier after aging. The contact barrier is higher for the RbF + S PDT sample, leading to decreased current in forward bias. Series resistance is also higher in the RbF + S PDT device which leads to lower fill factor. However, after aging the reference sample has a larger decrease in open‐circuit voltage (VOC). Ideality factor measurements suggest Shockley–Read–Hall recombination dominates both samples. VOC versus temperature and a temperature‐dependent activation energy model are used to calculate diode activation energies for each sample condition. Both techniques produce similar values that indicate recombination primarily occurs within the bulk absorber.

Non-negligibly negative role of e-waste-derived pyrogenic carbon in the soil washing of copper and polybrominated diphenyl ethers

The open incineration of electrical and electronic waste (e-waste) results in the accumulation of pyrogenic carbon in the soil. However, the effect of the e-waste-derived pyrogenic carbon (E-PyC) on the performance of soil washing at e-waste incineration sites remains unclear. In this study, the effectiveness of a citrate-surfactant mixed solution in removing copper (Cu) and decabromodiphenyl ether (BDE209) at two e-waste incineration sites was evaluated. The removal efficiencies of Cu (24.6–51.3%) and BDE209 (13.0–27.9%) were low in both soils and were not significantly improved by ultrasonic. Soil organic matter analysis, hydrogen peroxide and thermal pretreatment experiments, and microscale soil particle characterization demonstrated that the poor removal of soil Cu and BDE209 was due to steric effects of E-PyC on the release of the solid fraction of pollutants and the competitive sorption of the labile fraction of pollutants by E-PyC. Weathering of soil Cu weakened the influence of E-PyC but strengthened the negative impact of natural organic matter (NOM) on soil Cu removal by promoting complexation between NOM and Cu2+ ions. This study demonstrates that the negative effect of E-PyC on Cu and BDE209 removal by soil washing is non-negligible, which has implications for decontaminating e-waste incineration sites by soil washing.

Performance of biochar mixed cement paste for removal of Cu, Pb and Zn from stormwater

Using biochar as a partial replacement of Portland cement in cementitious materials is a promising solution to mitigate negative environmental impacts. However, current studies in available literature primarily focus on the mechanical properties of composites made with cementitious materials and biochar. Therefore, this paper reports the effects of the type of biochar, the percentage of biochar addition, and the particle size of the biochar on the removal efficiency of Cu, Pb, and Zn, as well as the effect of contact time on the removal efficiency of Cu, Pb, and Zn, along with the compressive strength. The peak intensities of OH−, CO32− and Calcium Silicate Hydrate (Ca–Si–H) peaks increase with increasing biochar addition levels, reflecting increased hydration product formation. The reduction of particle size of biochar causes the polymerization of the Ca–Si–H gel. However, no significant changes were observed in heavy metal removal, irrespective of the percentage of biochar addition, the particle size of biochar, or the type of biochar added to the cement paste. Adsorption capacities above 19 mg/g, 11 mg/g and 19 mg/g for Cu, Pb and Zn were recorded in all composites at an initial pH of 6.0. The Pseudo second order model best described the kinetics of the Cu, Pb, and Zn removal. The rate of adsorptive removal increases with the decrease in the density of the adsorbents. Over 40% of Cu and Zn were removed as carbonates and hydroxides through precipitation, whereas over 80% of Pb removal was via adsorption. Heavy metals bonded with OH−, CO32− and Ca–Si–H functional groups. The results demonstrate that biochar can be used as a cement replacement without negatively impacting heavy metal removal. However, neutralization of the high pH is needed before safe discharge.

Triggered heavy metals and chlorine simultaneous removal from hazardous waste incineration fly ash

To date, heavy metals and chlorine removal from hazardous waste incineration fly ash (HWI FA) by thermal treatment was scarcely reported. High content of calcium in HWI FA might affect heavy metals chlorination volatilization. The aim of this study was to realize heavy metals and chlorine simultaneous removal from HWI FA triggered by fluidized-bed municipal solid waste incineration fly ash (FBMSWI FA) during sintering. Results showed that the dilemma of low heavy metals removal efficiency was due to the dense structure and the difficulty of transformation of the stable phases including Cu2S, CuSiO3, and Zn2SiO4. By co-sintering with FBMSWI FA at the ratio of 1:1, the removal efficiency of Cu, Zn, Pb, Cd, and Cl reached as high as 84.4%, 92.0%, 99.9%, 99.5%, and 99.7%, respectively. Compared with the control, chlorination volatilization efficiency of Cu and Zn was significantly increased by 210.5% and 89.2%. The favourable promotion could be mainly attributed to Si/Al matrix in FBMSWI FA triggered the following reaction: i) Ca-bearing compounds in HWI FA were activated to destroy the dense structure, which facilitated the transformation of Cu2S to CuO; and ii) the conversion of NaCl and KCl to gaseous chlorine was promoted, which the formation of metal chlorides was accelerated.

Facile synthesis of chitosan-tartaric acid biosorbents for removal of Cu(II) and Cd(II) from water and tea beverages

Consumption of water and tea beverages leads to the intake of heavy metals by humans. Development of technology for decontamination greatly reduces the risks of the heavy metal exposure. In this study, environment-friendly chitosan-tartaric acid biosorbents (CTBs) were synthesized by a facile one-step cross-linking strategy to mitigate the Cu(II) and Cd(II) contamination in water and tea beverages. The cross linkage of tartaric acid and chitosan endowed CTBs with excellent properties in aspects of surface roughness, mechanical strength, and acid resistance. Adsorption performance and mechanism of CTBs were studied, and the Langmuir isotherm model and pseudo-second-order kinetic model were adhered during adsorption. Up to 90 % removal efficiencies of Cu(II) and Cd(II) from water and tea beverages by CTBs were achieved. Moreover, the adsorption showed only a slight reduction in the quality of tea beverages. This study offers a new insight for reduction of heavy metals-pollution in beverages.

Artificial neural network (ANN) modeling for simultaneous removal of a binary mixture of Pb(II) and Cu(II) by cobalt hydroxide nano‐flakes

AbstractA three‐layer artificial neural network (ANN) model was developed to predict the efficiency of Cu(II) and Pb(II) ion removal from aqueous solution by cobalt hydroxide nano‐flakes. It is based on experimental sets obtained from a D‐optimal design. The input variables to the neural network were as follows: the initial concentration of Pb(II) and Cu (II) ions (mg L−1), initial pH, and sorbent mass (g). The configuration of the backpropagation neural network for both Cu(II) and Pb (II) ions was a tangent sigmoid transfer function (tansig) at the hidden layer, linear transfer function (purelin) at the output layer, and Levenberg–Marquardt training algorithm (LMA). ANN‐predicted results were very close to the experimental results with a coefficient of determination (R2) of 0.9970 and mean square error (MSE) 0.000376. Analysis based on the ANN model indicated that sorbent mass appeared to be the most influential factor in the adsorption process of Cu(II) and Pb(II). Characterization of the cobalt hydroxide nano‐flakes and possible metal ions‐adsorbent interactions were confirmed by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM).