Initial Zn Concentration Research Articles

Evaluation of Two Levels of Trace Mineral Supplementation to Beef Calves Prior to Weaning.

In this 2-year study, approximately 84 days prior to weaning, 24 calves/year (Angus × Hereford) were randomly assigned to one of two treatments: trace mineral (Cu, Se, and Zn) supplementation following NASEM (2016) recommendations (Control) or trace mineral supplementation above NASEM (2016) recommendations (Super). Calves were individually fed, and trace minerals were provided in 0.5 kg of dry distiller's grains three times weekly. Body weight (BW), blood, and liver samples were collected on d 0 and at weaning (d 84). Additional BW and blood samples were collected post-weaning on d 85, 87, 88, 91, 95, and 99 during the preconditioning phase. Initial liver concentrations of Se, Cu, and Zn were similar between treatments (p ≥ 0.69). At weaning, a year effect (p < 0.001) and a tendency for treatment × year effect (p = 0.09) were observed for Cu liver concentration. In year 2, but not in year 1, calves assigned to the Super treatment tended to have greater liver Cu concentration than calves assigned to the Control treatment. Except for Cu, a notoriously limited trace mineral in multiple geographical locations, the supplementation of trace minerals above the NASEM (2016) recommendations did not improve the mineral status of calves in this environment.

Simultaneous removal of heavy metals and electricity generation from wastewater in constructed wetland-microbial fuel cells

Constructed wetlands (CWs) are environmentally friendly and cost-effective methods for wastewater treatment. Recently, there have been innumerable efforts to integrate CWs with microbial fuel cells (MFCs) to enhance the removal of pollutants while generating electricity. Constructed Wetland-Microbial Fuel Cells (CW-MFCs) are engineered systems incorporating physical, chemical, and biological processes for wastewater treatment. However, the application of CW-MFCs to remove multiple heavy metals from wastewater is still an active area of research. The present study explores for the first time the utilization of different types of CW-MFCs, including CW-MFC-planted, CW-MFC-unplanted, and CW-sand-filter for simultaneous removal of different concentrations of organic pollutants and multiple heavy metals such as zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) from wastewater while generating electricity. The study employed nine CW-MFC microcosms, some of which were planted with Phragmites australis. The initial concentrations of Cu, Pb, Zn, and Cd were maintained at 2, 10, and 30 mg/l, respectively, while initial COD concentrations were 120, 500, and 1000 mg/l. Remarkably, the maximum removal rates achieved were 98.83 %, 95.74 %, 92.91 %, and 90.75 % for Cu, Pb, Zn, and Cd, respectively, and the maximum removal rate of COD was 97.96 % at 10 mg/l of Cu, Pb, Zn, Cd, and 500 mg/l of COD in CW-MFC-planted. The attained highest voltage, current, and power densities reached 687 mV, 4000 mA/m3, and 785.86 mW/m3, respectively, in CW-MFC-planted. This study demonstrates the significant impact of CW-MFC-planted systems on wastewater treatment and electricity generation.

Highly efficient recovery of Zn (II) from zinc-containing wastewater by tourmaline tailings geopolymers to in-situ construct nanoscale ZnS for the photodegradation of tetracycline hydrochloride

While treating zinc-containing wastewater, recovering zinc for reuse as a secondary resource has significant environmental and economic benefits. Herein, based on the alkali-activated tourmaline tailings geopolymers (TTG) after adsorption of zinc ions (Zn (II)), a series of new composites with in-situ construction ZnS nanoparticles on TTG (ZnS/TTG) were synthesized, and used as photocatalysts for the photodegradation of tetracycline hydrochloride (TCH) in solution. Specifically, ZnS nanoparticles were uniformly and stably distributed in the layered structure of TTG, interweaving with each other to generate an interfacial electric field, which could induce more photocarrier generation. Meanwhile, TTG acted as an electron acceptor to accelerate the electron transfer at the interface, thus enhancing the photodegradation activity for TCH. The active radical quenching experiments combined with the ESR indicated that the active species produced during the photocatalytic degradation of TCH by ZnS/TTG composites were •O2− and photogenerated h+. When the initial concentration of Zn (II) was 60 mg/L, the synthesized 60-ZnS/TTG composites (0.5 g/L) reached 91.53% degradation efficiency of TCH (10 mg/L) at pH = 6. Furthermore, the possible pathways and mechanism of 60-ZnS/TTG composites photodegraded TCH were revealed with the aid of degraded intermediates. This report not only proposed valuable references for reusing heavy metal ions and removing TCH from wastewater, but also provided promising ideas for realizing the conversion of used adsorbents into high-efficiency photocatalysts.

Viability and life cycle assessment of Fuller's Earth as a low-cost adsorbent for zinc removal from aqueous solutions: Operating parameters, removal mechanisms and environmental impacts

Zinc is a heavy metal that has several health risks and must be removed from wastewater effluents before discharge to water bodies or reuse. Fuller's earth is a sedimentary clay and characterized by its low cost and availability. In this research, Fuller's earth (FE) was investigated as an adsorbent for the Zinc (Zn) removal from aqueous solutions to understand its performance, the mechanism of removal, and the potential environmental impacts. Life cycle assessment (LCA) was conducted using ReCiPe 2016 midpoint method. Zn adsorption studies on FE were conducted at various pH (2.5–9), temperatures (10°C, 25°C, and 40°C), initial concentrations of Zn (25, - 150 mg/L) and adsorbent doses of (0.25–4 g/ 50 ml). The Zn removal efficiency reached 99% at pH = 9 at an initial Zn concentration = 100 mg/L and the adsorbent dose = 0.25 g/ 50 ml. The experimental data fit into the Temkin isotherm, while kinetics were best expressed by pseudo-second order. The controlling step of the adsorption process was the film diffusion according to Boyd model. Thermodynamic experiments showed that adsorption is endothermic with an accompanying rise in randomness in the system. The adsorption capacity was 3.56 mg/g. Images by SEM confirmed the occurrence of adsorption. The desorption was successful at different concentrations of HCl. LCA results showed that the maximum negative and positive environmental impacts were associated with mineral resource scarcity (7.5*10–5 kg Cu eq) and human non-carcinogenic toxicity (−0.821 kg 1,4-DCB), respectively.

203 The relationship between potentiated zinc oxide and monovalent copper in a dietary administration for weanling piglets

Abstract The aim of this study was to evaluate different dietary level of Zinc (Zn) and Copper (Cu) supplementation according to European and non-European levels on the health and performance of pigs 14 d after weaning. A total of 120 piglets [initial body weight = 7.14 ± 0.92 kg] were divided into 4 experimental treatments: positive control (PC, 2,500 ppm of Zn, ZnO) and 3 treatments in which Zn and Cu were added through potentiated ZnO and Cu2O according to different European and non-European levels of inclusion: EU (120 ppm of Zn; 140 ppm of Cu), non-EU+ (300 ppm of Zn; 200 ppm of Cu) and non-EU- (300 ppm of Zn; 140 ppm of Cu). Growth performance, serum Zn and Cu concentrations, fecal score, blood biomarkers of intestinal integrity, and fecal microbial composition were examined and analyzed using GLM and MIXED procedures of SAS. Fecal samples at 14 d were collected and the V3–V4 hypervariable regions of the bacterial 16S gene were sequenced in one Illumina MiSeq run. Body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR) and (feed efficiency (FE) were not affected by the experimental treatments. The fecal score suggests that during the first 14d, the consistency of the feces tended (P &amp;lt; 0.10) to be less in the three treatment groups while in PC, the greatest concentration of Zn favored a better fecal consistency. The initial serum Zn and Cu concentrations were similar for all dietary treatment groups. After 14 d, serum Zn concentration was significantly greater in PC (15.71 ± 6.25 µg/L, P &amp;lt; 0.05). No differences were highlighted in serum Zn concentration among the other 3 treatment groups. Serum Cu concentrations revealed statistically significant results (P &amp;lt; 0.05) on 14 d after weaning in EU, non-EU+ and non-EU- groups, showing greater concentrations of Cu (17.65 ± 5.49 µmol/L, 17.73± 3.46 µmol/L 18.33 ± 4.13 µmol/L, respectively) compared with PC (11.87 ± 3.60 µmol/L). These results suggested that the EU level of inclusion of both potentiated Zn and monovalent Cu is enough to reach the same Cu and Zn plasma concentrations of non-EU treatments. Plasma DAO was negatively (P &amp;lt; 0.05) affected in non-EU-. Firmicutes and Bacteroidetes were the most abundant phyla in fecal microbiome. Non-EU- contributed to a significant decrease in biodiversity in fecal microbiota as depicted with Shannon for diversity and Simpson for evenness indexes (P &amp;lt; 0.05). In fecal samples, the presence of genera linked to a greater disruption of the gut barrier (Escherichia-Shigella) was depicted in non-EU- group, indicating significant modifications of the microbial community. These results suggest the need for a balanced supplementation of Cu and Zn through more bioavailable sources. The use of potentiated ZnO and Cu2O according to European levels could represent a valid strategy to enhance weanling piglets gut health and to reduce the environmental impact.

Effects of humic acid and mineral Zn fertilizer on Zn uptake and maize yield in soils formed on limestone and marl parent materials

In this study, the effects of zinc (Zn) and humic acid (HA) applications on soils (12 Aridisol soil samples) formed on limestone and marl parent materials, which are very common in Türkiye, were tested by incubation, adsorption, and greenhouse experiments. Adsorption experiments were carried out using the batch sorption technique, and the Langmuir and Freundlich isotherm parameters were calculated. In the incubation, soils were incubated with control, HA, Zn, and HA+Zn, and the DTPA-Zn was tested in five different periods (1, 7, 15, 30, and 90th days). Maize was grown for eight weeks in pots in the greenhouse. The maximum Zn adsorption for all soils ranged between 3333 and 6250 mg kg-1 in marl soils and 1042 and 5263 mg kg-1 in limestone soils, which decreased to ranges between 2631 and 5555 mg kg-1 in marl soils and 1052 and 5000 mg kg-1 in limestone soils with HA appli-cation, respectively. The desorption rate (%) of adsorbed Zn increased as the initial Zn concentration increased in all soil series formed on marl (smectite clay mineral) and lime-stone (kaolinite clay mineral) parent materials. The effects of humic acid and Zn applica-tion on the fresh and dry weights of maize were found to be statistically significant at the 5% level for marl and limestone parent material. Humic acid application increased the fresh weight of maize compared with that of the control. The highest available Zn was determined in Başkuyu series (0.79 mg kg-1) formed on marl parent material, while the lowest available Zn was obtained in Saraççeşme series (0.60 mg kg-1) formed on limestone parent material. In the greenhouse, HA increased the fresh weight of maize in soils formed on both parent materials by 0.4 and 19.6%, respectively, compared to the control. Zn fertili-zation with HA further increased the fresh and dry yields, with 12 mg kg-1 performing bet-ter. Smax (maximum Zn adsorption of the soil) parameters of soils were negatively corre-lated with EC, Pav, Kav, organic matter, silt, clay, total N, and cation exchange capacity (CEC) of the samples. Although HA alone increases the availability of Zn in plants, HA + Zn appli-cations should be applied together to obtain higher yields.

Competitive Adsorption of Cd(II) and Zn(II) on Biochar, Loess, and Biochar-loess Mixture

Combined heavy metal contamination in soil is a common phenomenon. Biochar amendment into the soil is considered to be an alternative for immobilization remediation of soil contaminated with heavy metals due to its adsorption and alkalization. However, much attention has been paid to the adsorption and immobilization of single heavy metals by biochar. In this paper, the competitive adsorption of Cd(II) and Zn(II) on biochar derived from cotton straw and pig manure at 500℃ (BCS500 and BPM500), loess and biochar-loess mixtures were investigated using the batch equilibrium method. The results showed that the adsorption capacities of biochars, loess, and biochar-loess mixtures to Cd(II) and Zn(II) in the mixed Cd-Zn systems increased with the increase of initial metal concentrations of Cd(II) and Zn(II). The adsorptive capacities of BCS500 and BPM500 to Cd(II) in mixed Cd-Zn system were 33% and 35% less than those in the single Cd(II)systems, while the adsorptive capacities to Zn(II) were 62% and 56% less than those in the single Zn(II) systems. The adsorptive capacities of loess to Cd(II) and Zn(II) in mixed Cd-Zn systems were 29% and 55% less than those in the single metal systems. The adsorptive capacities of loess-BCS500 (LBCS) and loess-BPM500 (LBPM) to Cd(II) in mixed Cd-Zn system were 40% and 38% less than those in the single Cd(II) systems, while the adsorptive capacities to Zn(II) were 63% and 60% less than those in the single Zn(II)systems. Moreover, the competitive adsorptive capacity of Cd(II) is greater than that of Zn(II). It can be seen that when heavy metal pollution with similar nature of multiple elements exists in soil, the amount of adsorbent should be increased to resist the possible weakened adsorption caused by competitive adsorption in order to guarantee an effective absorption treatment.

Sustainable and integrated approaches for carbon capture and rapid remediation of Cr- and Zn-contaminated soils

Soil contamination is a growing concern for sustainable development worldwide. Conventional remediation approaches, such as using ordinary Portland cement (OPC) or lime are limited due to high CO2 emissions, energy consumption, and natural resource consumption. This paper proposes a sustainable method using CO2 and a waste from steel production (ladle slag, LS) for rapid remediation of Cr and Zn-contaminated soils. Contaminated soils spiked by Cr and Zn with various initial concentrations were treated with 10% LS and subjected to conventional and CO2 curing for different periods. The results demonstrated that LS with conventional curing could reduce leaching concentrations of Cr and Zn in contaminated soils. However, it necessitated 28 days to meet the criteria of inert waste and drinking water standards. In contrast, LS with CO2 curing required significantly less time (32 h for Cr and 8 h for Zn) to achieve lower leaching concentrations of Cr and Zn than those with 28-day conventional curing. After CO2 curing for 152 h for Cr- and 80–120 h for Zn-contaminated soils, leaching concentrations of Cr and Zn were 1.5–4 times and 6–72 times lower than those with 28-day conventional curing, respectively. Simultaneously, carbon capture was increased from 10.6% to 17.5% and 19.9%, respectively, with the initial Cr and Zn concentrations increased from 0 to 8000 mg/kg. The strength of Cr- and Zn-contaminated soils with CO2 curing also effectively enhanced up to around 3.3–3.6 times and 1.3–3.3 times higher than those with 28-day conventional curing, respectively.

Adsorption performance of bentonite and clay for Zn(II) in landfill leachate

BackgroundThe increasing prevalence of the Galvanized and dry battery industries has led to a rise in zinc proportions in landfills, posing environmental risks. This study explores the potential of bentonite, renowned for its metal adsorption capability, as a landfill barrier material.MethodsAdsorption characteristics of Zn(II) in natural bentonite and Shanghai clay were investigated. Various factors affecting Zn(II) adsorption, including pH, Na ion strength, contact time, initial Zn(II) concentration, and adsorption temperature, were analyzed through batch-type adsorption tests.ResultsThe change in pH and Na strength demonstrates no significant impact on the adsorption of Zn(II) onto bentonite, highlighting the strong selectivity of bentonite for Zn(II). Conversely, the equilibrium adsorption capacity of Zn(II) onto clay increases with rising pH or decreasing ion strength. The Zn(II) adsorption onto bentonite is well-described by the pseudo-second-order, intra-particle diffusion, and Elovih models, each achieving an R2 value exceeding 0.9. While both physical and chemical adsorption coexist in Zn(II) adsorption onto bentonite or clay, the primary determinant of the adsorption rate is chemical adsorption. The adsorption onto bentonite is spontaneous, whereas onto clay it is not. The mechanism involves van der Waals forces, ion exchange, and chemical actions such as inner-sphere complexation for Zn(II) adsorption onto both bentonite and clay.

Adsorption thermodynamics and kinetics of hydrochloric-acid-modified bentonite for Zn(II) in wastewater

In order to study the Zn(II) adsorption characteristics of hydrochloric-acid-modified bentonite in wastewater, physical characterization of hydrochloric-acid-modified bentonite was carried out, the effects of the initial concentration, reaction time, and temperature on the Zn(II) adsorption were investigated, and the adsorption kinetics and thermodynamic mechanism of the hydrochloric-acid- modified bentonite adsorption of Zn(II) were examined. The results showed that hydrochloric acid modification increased the interlayer spacing of the bentonite, and the structure of the binding between slices became looser. Hydrochloric acid modification altered the hydroxyl groups on the bentonite surface, and the hydrophilicity was enhanced. The Zn(II) adsorption capacities of bentonite and hydrochloric-acid-modified bentonite increased with the increase in the initial Zn(II) concentration, and the adsorption followed the Langmuir and Freundlich equations. The thermodynamic parameters suggested that the adsorption of Zn(II) was an endothermic, spontaneous, and entropy-increasing process. The adsorption basically reached equilibrium within 120 min, and the adsorption followed the quasi-second-order adsorption kinetic equation. The adsorption process was mainly chemical adsorption, and the intra-particle diffusion process was not the only step controlling the adsorption rate. This study provides a theoretical basis for the remediation of toxic metal wastewater and contaminated soil.

Molecular imprinting of cellulose cotton fabric/silica materials with a colorimetric dithizone chelation for smartphone‐based detection of Zn (II) ions in water samples

AbstractMolecularly imprinted materials based on imprinting dithizone‐Zn (II) (DTZ‐Zn (II)) complexes onto cotton fabric/silica, and the Color Grab application for the OPPO A54 smartphone, were proposed and applied for the first time to detect Zn (II) ions in water samples. The proposed materials were prepared by using cotton fabrics as cellulosic materials, tetraethoxysilane as silica sources and DTZ‐Zn (II) as template molecules. The initial concentration of DTZ and Zn (II), the volume of tetraethoxysilane and the reaction time were optimised to obtain the maximum adsorption of the DTZ‐Zn (II) complexes in the imprinted materials. The concentration of hydrochloric acid and the extraction time were optimised to obtain the maximum Zn (II) removal. The results found that 10 mL of a solution containing DTZ (0.20 mM) and Zn (II) (0.30 mM), 25 μL of tetraethoxysilane, with 10 minutes reaction time, exhibited the strongest binding of the template complexes. Zn (II) ions were selectively removed from the materials by using 0.1 M hydrochloric acid for 10 minutes. The morphology of the prepared materials was characterised by scanning electron microscopy–energy‐dispersive X‐ray spectroscopy and attenuated total reflectance–Fourier Transform‐infrared spectroscopy. The smartphone measurement based the cotton fabric/silica materials exhibited linear relationship between saturation (%) and Zn (II) concentrations in the range of 0.1 to 1.0 mg/L, with limit of detection of 0.02 mg/L and limit of quantification of 0.06 mg/L. The proposed method was successfully applied to determine Zn (II) in real‐water samples with the % recovery ranging from 98% to 115% and an acceptable relative standard deviation of less than 6 (n = 3).

Entrapment of green seaweed Caulerpa Scalpelliformis for extracting Pb(II), Ni(II) and Zn(II) metal ions from aqueous solutions

&lt;p&gt;From this study, green seaweed Caulerpa Scalpelliformis is utilized as a sorbent for the removal of three metals such as lead (Pb), nickel (Ni) and zinc (Zn). Adsorption tests showed that maximum removal efficiency of 75.02% for Pb, 80% for Ni and 91.11% for Zn was obtained at an optimal equilibrium pH of 7 for Pb and 6 for Ni, Zn, 2g/L sorbent at an ionic strength of 100 mg/L of 30°C. Four isotherm models, such as Langmuir, Freundlich, Toth, and Sips used in this study to determine the correct fit model from test results. The toth model (R2=0.999) was well fit compared to other isotherms models based on correlation coefficients. Kinetic model results obtained at initial Pb, Ni and Zn concentrations revealed a high biosorption rate. In contrast, the results have been modelled effectively with the pseudo-first and second orders. As a result, tests with elutants found that 0.1M HCl is the perfect desorption elutant for three metal ions.&lt;/p&gt;&#x0D;

Investigation of performance and mechanism of zinc removal from polluted water by concrete fines derived from aggregate recycling: From problematic byproducts to effective adsorbent

Concrete fines are byproducts produced from aggregate recycling. Because of their properties, they cannot be directly recycled for use in concrete manufacturing, which is problematic to move the cement and concrete industry toward sustainable development goals and reduce its environmental impact. Taking advantage of concrete fines unique properties was regarded as a possible research direction. The hydrated cement fraction was expected to provide alkalinity to neutralize the acidic solutions, while calcium related compounds were expected to provide the function of heavy metals removal. In this research, concrete fines were used to remove Zn from acid mine drainage as an active treatment. The removal performance was comprehensively investigated. The maximum capacity of Zn-adsorption is 111.9 mg/g, and almost 100% Zn can be removed for an initial Zn concentration of 20 mg/L. The dominant reaction mechanism of Zn adsorption to concrete fines was determined to be ion-exchange reaction with surface complexation and precipitation. The Zn2+ ions in solution can exchange with the Ca2+ ions in calcium silicates and calcium silicate hydrates in concrete fines and replace the protons released by ionization of the silanol group for complexation, and thus Zn removal is not limited to an alkaline environment or high initial Zn concentration. The acidity was alkalized by hydration reaction, mainly consuming calcium hydroxide. Based on these mechanisms, concrete fines are effective adsorbent to remove Zn without the need for the synergistic reactions of other metals and for making the aqueous solution strongly alkaline, even in the strongly acidic environments and in effluents with high Zn concentration. Through evaluation and comparison of Zn adsorption capacity with other materials, concrete fines were regarded as promising alternative adsorbent for Zn removal.

Immobilized sulfate reducing bacteria (SRB) enhanced passivation performance of biochar for Zn

The low survival rate in harsh environments has been hindering the transformation of microbial remediation technology for heavy metal-contaminated soil from laboratory to field application. Therefore, biochar was selected as the carrier in this study to immobilize the heavy metal tolerant sulfate-reducing bacteria of SRB14-2-3 for the passivation of Zn-contaminated soil. The results showed that the immobilized bacteria of IBWS14-2-3 exhibited the highest passivation performance, as the total content of bioavailable Zn fractions (exchangeable + carbonates) in soil with initial Zn concentration of 350, 750 and 1500 mg·kg−1 decreased by almost 34.2 %, 30.0 % and 22.2 % compared to the control group, respectively. In addition, the introducing of SRB14-2-3 into biochar has successfully alleviated the possible adverse effects on soil caused by the application of large amounts of biochar, while the protection of biochar against immobilized bacteria significantly improved the reproduction of SRB14-2-3, since the number of SRB14-2-3 increased by 82,278, 42 and 5 times in three different level contaminated soil. Furthermore, the new passivation mechanism for heavy metals brought by SRB14-2-3 is expected to make up for the deficiency of biochar in long-term application. And more attention should be paid on the performance of immobilized bacteria under field practical application in the future research.

In situ/operando XAFS investigation of the sorption/precipitation of Zn(II) on palygorskite surface at the molecular scale: Implications for Zn stable isotope fractionation

In aqueous geological environments, the fate and transport of Zn are controlled by geochemical reactions (e.g., sorption) occurring at the mineral/water interface. However, many of the underlying Zn fixation mechanisms, especially the kinetics of surface-induced precipitation, are still unclear. Additionally, Zn stable isotope fractionation during sorption has recently been shown to be an important process, but the relationship between Zn isotope fractionation and sorption mechanisms (e.g., surface complexation, precipitation) is also not well understood. To address these issues, we employed X-ray absorption fine structure (XAFS) spectroscopy, high-resolution transmission electron microscopy (HRTEM), and in situ/operando quick-scanning XAS (QXAS) spectroscopy to elucidate the sorption/precipitation mechanisms of Zn at palygorskite/solution interfaces. We also measured Zn isotope ratios during some sorption experiments to illustrate how Zn isotope fractionation behavior is affected by the evolution of coordination environments at different pH values, initial concentrations, and reaction times. Our results demonstrate that Zn sorption mechanisms vary as a function of pH, ionic strength, initial concentration, and reaction time. At low pH (pH < 7.0) and low ionic strength (I ≤ 0.01 M), Zn(II) predominantly forms an outer-sphere surface complex in octahedral coordination. At low pH (pH < 7.0) and high ionic strength (I = 0.1 M), Zn(II) is predominantly sorbed as an inner-sphere octahedral surface complex with insignificant isotopic fractionation (Δ66Znsorbed-aqueous = −0.02 ± 0.05‰). At high pH and high initial Zn concentration (pH 7.5, C0 ≥ 0.2 mM), the formation of octahedral Zn phyllosilicate precipitates is observed, yielding a small fractionation with an average Δ66Znsorbed-aqueous of 0.10 ± 0.07‰. In addition, in situ/operando QXAS of Zn sorption at pH 7.5 in a flow cell revealed that the predominant sorbed Zn species shifted from inner-sphere tetrahedral complexes during the initial stage (e.g., within minutes) to inner-sphere octahedral complexes during later stages (e.g., within hours), followed by the formation of Zn-phyllosilicate precipitates (e.g., within days). This molecular evidence coincides with the evolution of Zn isotope fractionation from a large Δ66Znsorbed-aqueous value (0.53 ± 0.05‰) to a small value of 0.05 ± 0.04‰ during the sorption process. The combination of QXAS and isotope fractionation results reveals a change in the Zn local environment from tetrahedral coordination to octahedral coordination. The findings in this study not only provide new insight into surface adsorption/precipitation mechanisms but also demonstrate that stable isotope fractionation is linked with the local molecular/bonding environments at mineral–water interfaces.

Zn(II) removal from wastewater by an alkali-activated material prepared from steel industry slags: optimization and modelling of a fixed-bed process

ABSTRACT Removal of dissolved zinc (Zn) from water by a novel alkali-activated material (AAM) prepared from steel industry slags in a fixed-bed column was investigated. Design of experiments was used to find the optimum operation parameters [flow rate ( Q ) , adsorbent mass, ( m ads ), and initial Zn concentration ( C 0 )] for the removal of Zn2+ from a ZnCl2 solution. Regression models for the breakthrough ( q b ), and saturation ( q sat ) capacities of the bed and three other response parameters as functions of Q , m ads and C 0 were fitted with coefficients of determination ( R 2 ) ranging from 0.48 to 0.99. Experimental values of q b and q sat varied within 1.42–7.03 mg Zn/g and 10.57–17.25 mg Zn/g, respectively. The optimum operation parameters were determined to be Q = 1.64 ml/min and m ads = 4.5 g, whereas C 0 had negligible effect on the response parameters in the range 73–107 mg Zn/l. Finally, three empirical breakthrough curve (BTC) models were employed to describe the individual BTCs of which the modified dose – response model was found to give the best fit (0.960 ≤ R 2 ≤ 0.998). The results of the present work demonstrate that the novel AAM has considerable potential to be utilized in water purification applications.

The Effect of Metals of the 2nd and 12th Groups on the Productivity and Selectivity of Cumene Oxidation—The First Stage of the Technological Chain for the Production of Polymer Composites

The effect of the process temperature and the initial concentration of Mg, Ca, Sr, Ba, Zn, Cd, and Hg 2-ethylhexanoates as catalysts on the productivity and selectivity of the oxidation stage of cumene is studied in the technological chain for the production of polymer composites from cumene; “production of phenol by cumene method (stage 1 is cumene oxidation to cumene hydroperoxide, stage 2 is decomposition of cumene hydroperoxide into phenol and acetone) → production of precursors from phenol → production of polymers from precursors → production of composites from polymers”. A criterion has been introduced that reflects the productivity of cumene oxidation at the moment of reaching the maximum concentration of cumene hydroperoxide, which takes into account the cumene conversion and selectivity achieved in this case in the shortest possible time using the selectivity comparable with the selectivity of a non-catalytic process. It has been shown that the achievement of the maximum value of this criterion, among all the considered catalysts, is ensured by Mg 2-ethylhexanoate at its relatively low initial concentration (1 mmol/L) under conditions of moderately-high process temperatures (393–413 K).

Synthesis, characterization and analytical applications of cobalt ferrite nanoparticles

• CoFe 2 O 4 nanoparticless have been prepared. • The isolated nanoparticles have been characterized by IR, XRD, TEM and SAED • The analytical applications of CoFe 2 O 4 have been studied. A simple, rapid, and reliable method for adsorptive separation and pre-concentration of Zn(II) ions in aqueous solution using cobalt ferrite nanoparticles as adsorbent followed by spectrophotometric determination has been developed. Cobalt ferrite nanoparticles (CFNs) have been synthesized by co-precipitation method and characterized by infrared (IR), x-ray powder diffraction (XRD), high resolution transmittance electron microscope (HR-TEM) and selected area electron diffraction (SAED). The results indicated that the average particle size is 8.0 nm. The results of the adsorptive separation and pre-concentration of Zn(II) ions using CoFe 2 O 4 nanoparticles as adsorbent showed an extraction recovery > 98% from 50 mL aqueous sample at pH 8, initial Zn(II) concentration 0.05 mg/L, adsorbent dose 2 g/L and 2 mL of 0.5 M HNO 3 as eluent. The pre-concentration factor obtained was 25 under these optimum conditions. The pre-concentration factor obtained was 25 under ideal experimental circumstances. The suggested method was successfully applied for determination of trace zinc concentrations in several water samples using flame atomic absorption spectrophotometry and satisfactory results were obtained.

362 Evaluation of Different Levels of Trace Mineral Supplementation to Calves Prior to Wearing

Abstract A two-year study evaluated two different levels of trace mineral supplementation (Cu, Se, and Zn) to calves prior to weaning. Approximately 84 days prior to weaning, 24 calves/year (Angus × Hereford) were randomly assigned to one of two treatments: trace mineral supplementation following NASEM (2016) requirements (Control); and trace mineral supplementation above NASEM (2016) requirements (Super). Calves were individually fed and trace minerals were provided in 0.5 lb of dry distillers grains three times weekly. The total weekly amount of trace minerals was divided into three feeding events (Monday, Wednesday, and Friday). Body weight (BW), blood, and liver samples were collected on d 0 and at weaning (d 84). All data were analyzed using the MIXED procedure (SAS Inst. Inc., Cary, NC). No differences (P ≥ 0.69) were observed for the initial liver concentration of Se, Cu, and Zn. No differences (P = 0.54) were observed for liver Se concentration at weaning. A year effect (P &amp;lt; 0.0001) and a tendency for treatment x year effect (P = 0.09) were observed for liver Zn concentration at weaning. In year 1 but not in year 2, calves assigned to Control treatment had greater liver Zn concentration than calves assigned to Super treatment. For Cu liver concentration, a year effect (P &amp;lt; 0.0001) and a tendency for treatment x year effect (P = 0.09) were observed at weaning. In year 2, but not in year 1, calves assigned to Super treatment had greater liver Cu concentration than calves assigned to Control treatment. No treatment effects (P ≥ 0.23) were observed for BW or average daily gain pre- or post-weaning. Except for Cu, supplementation of trace minerals above the NASEM (2016) recommendations does not lead to improved mineral status of calves in this environment.

Single-stage microwave assisted coconut shell based activated carbon for removal of Zn(II) ions from aqueous solution – Optimization and batch studies

Health and environmental issues associated with heavy metal ions have received serious attention from communities worldwide. This work explores the potential of coconut shell as activated carbon (CSAC), in adsorbing zinc, Zn(II) ions. This adsorbent was prepared via a single-stage microwave irradiation technique under the flow of carbon dioxide, CO 2 gas. CSAC posed BET surface area of 625.61 m 2 /g, 513.25 m 2 /g of mesopores surface area, total pore volume of 0.42 cm 3 /g, and average pore diameter of 4.55 nm. Zeta potential distribution on CSAC was found to be −21 mV. Response surface methodology (RSM) had suggested that the optimum values of variables were 450 W and 3.17 min for radiation power and radiation time respectively, which resulted in 69.65% of Zn(II) removal and 44.32% of CSAC’s yield. Based on F-value, radiation power (473.62) and radiation time (140.50) posed major and moderate effects on Zn(II) removal, respectively. Meanwhile, CSAC’s removal was significantly affected by radiation power (78.84) and less affected by radiation time (7.06). In a batch study, when the initial concentration of Zn(II) was increased, Zn(II) uptakes increased as well. On contrary, Zn(II) removal percentage decreased with the increase of Zn(II)’s initial concentration. Multilayer adsorption of Zn(II) onto CSAC had occurred since this adsorption system followed Freundlich isotherm the best, and the monolayer adsorption capacity, Q m for Zn(II) was revealed to be 7.87 mg/g. The kinetic data of the Zn(II)-CSAC adsorption system was best described by pseudo-first-order (PFO) which indicated the role of physisorption. In the regeneration study, CSAC’s mass and Zn(II) adsorption uptakes had reduced from 100% to 37% and 77%, respectively, after 6 regeneration cycles.