Search

The crystal structure of the title compound, hexaaquanickel(II) dichloride- 1,4,7,10,13,16-hexaoxacyclooctadecane-water (1/2/2), [Ni(H2O)6]Cl2- 2C12H24O6183;2H2O, is reported. The asymmetric unit contains half of the Ni(OH2) 6 moiety with a formula of C12H32CINi0.50O10 at 105 K and triclinic (P1) symmetry. The [Ni(OH2)6]2+ cation has close to ideal octahedral geometry with O-Ni-O bond angles that are within 3° of idealized values. The supra- molecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl- anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH2)6]2+ molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl- counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH2)6]2+. [ABSTRACT FROM AUTHOR]

Fungal biomass is as a cost-effective and sustainable biosorbent utilized in both active and inactive forms. This study investigated the efficacy of inactivated and dried biomass of Fusarium sp. in adsorbing Ni2+ and Pb2+ from aqueous solutions. The strain underwent sequential cultivation and was recovered by filtration. Then, the biomass was dried in an oven at 80 ± 2 °C and sieved using a 0.1-cm mesh. The biosorbent was thoroughly characterized, including BET surface area analysis, morphology examination (SEM), chemical composition (XRF and FT-IR), thermal behavior (TGA), and surface charge determination (pH-PZC and zeta potential). The biosorption mechanism was elucidated by fitting equilibrium models of kinetics, isotherm, and thermodynamic to the data. The biosorbent exhibited a neutral charge, a rough surface, a relatively modest surface area, appropriate functional groups for adsorption, and thermal stability above 200 °C. Optimal biosorption was achieved at 25 ± 2 °C, using 0.05 g of adsorbent per 50 mL of metallic ion solution at initial concentrations ranging from 0.5 to 2.0 mg L−1 and at pH 4.5 for Pb2+ and Ni2+. Biosorption equilibrium was achieved after 240 min for Ni2+ and 1440 min for Pb2+. The process was spontaneous, mainly through chemisorption, in monolayer for Ni2+ and multilayer for Pb2+, with efficiencies of over 85% for both metallic ion removal. These findings underscore the potential of inactive and dry Fusarium sp. biomass (IDFB) as a promising material for the biosorption of Ni2+ and Pb2+. [ABSTRACT FROM AUTHOR]

The removal of Congo red (CR) and heavy metal ion nickel (Ni(II)) from wastewater is a critical concern for safeguarding the aquatic environment and promoting sustainable development. Herein, a novel citric acid steam-assisted decomposition method is applied to form meso-macroporous magnesium oxide (MgO) with rich oxygen defects. As the gelation process of xerogel precursor could be significantly promoted by the steam-assisted process with citric acid solution as steam source, the morphology structure of MgO changes into loose aggregates with sharp edges and is covered by a layer of MgO nanoparticles. The synthesized MgO, with a high surface area (103.60 m2 g−1), meso-macroporous structure and abundant oxygen defects, exhibits super adsorption capacities for CR (7109.85 mg g−1) and Ni(II) (1405.88 mg g−1). The MgO (0.4 g L−1) could completely remove CR (200 mg L−1) in 30 min, while 10 min for Ni(II) (200 mg L−1) adsorption. The adsorption mechanism of MgO for CR and Ni(II), including electrostatic interaction, oxygen vacancy capture, hydrogen bonding and ion exchange, is effectively enhanced due to the appearance of meso-macroporous structure and oxide defects, such as 5-coordinated oxygen anion (O 5C 2−) for terrace, 4-coordinated oxygen anion (O 4C 2−) for edge and 3-coordinated oxygen anion (O 3C 2−) for corner. The easy calcination is applied to recycle MgO after CR adsorption and the CR removal efficiencies are above 98 % after five cycles. Meanwhile, a nickel chelator (Na 2 EDTA) and calcination are used to regenerate the MgO after Ni(II) adsorption and the adsorbent shows an insignificant removal efficiency loss after three cycles. The meso-macroporous MgO with rich oxygen defects has the characteristics of high adsorption speed, high adsorption capacity and convenient recovery property, and is expected to become an ideal material for the rapid treatment of high concentration wastewater. [ABSTRACT FROM AUTHOR]

The crystal structure of the title compound, hexaaquanickel(II) dichloride–1,4,7,10,13,16-hexaoxacyclooctadecane–water (1/2/2), [Ni(H2O)6]Cl2·2C12H24O6·2H2O, is reported. The asymmetric unit contains half of the Ni(OH2)6 moiety with a formula of C12H32ClNi0.50O10 at 105 K and triclinic (P1) symmetry. The [Ni(OH2)6]2+ cation has close to ideal octahedral geometry with O—Ni—O bond angles that are within 3° of idealized values. The supramolecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl− anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH2)6]2+ molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl− counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH2)6]2+.

A series of novel asymmetric alkyl P‐substituted bis(phosphanyl)amine (PNP) Ph2PN (cyclopentyl) PR1R2‐type L1–L5 ligands and these corresponding Ni(II) precatalysts C1–C5 were synthesized and characterized. The structures of these complexes were confirmed by using 1H‐, 31P‐, 13C‐NMR, FT‐IR, and elemental analysis. Using ethylaluminum dichloride (EADC) as a cocatalyst, nickel complexes exhibited high activity in elective ethylene oligomerization, with the main products being dimers and a small number of trimers. Under optimized conditions of 60°C and 1.0 MPa ethylene pressure, C4, bearing a diisopropylphosphoryl group, exhibited highest catalytic activity of 1342.9 kg·g Ni−1·h−1 with 85.2% C4 and 14.8% C6 products selectivity, while C2, bearing a diethylphosphonyl group, showed catalytic activity of 596.4 kg·g Ni−1·h−1 with 88.2% C4 and 11.8% C6 product selectivity. Single crystal analysis offered a more comprehensive insight into the subtle effects of alkyl P‐substituted in the scaffold of C2 and C4 ligands on catalytic activity. Density functional theory (DFT) calculations indicated that lower energy of the LUMO in the C4A intermediate enhances the activity of ethylene oligomerization. It provides a new method for purposefully designing ligands for ethylene oligomerization with high catalytic activity. [ABSTRACT FROM AUTHOR]

We have successfully synthesized a new Ni(II)‐based coordination polymer (CP) [Ni2(cis‐1,4‐chdc)2(4,4′‐bpy)3(H2O)2] (1); (cis‐1,4‐ H2chdc=cis‐1,4‐cyclohexanedicarboxylic acid and 4,4′‐bpy=4,4′‐bipyridine) employing slow diffusion method in a single pot technique. The connectivity of Ni(II) ions and bridging cis‐1,4‐chdc ligand gives rise to a three‐dimensional (3D) framework with 2‐fold interpenetrated diamondoid topology. Interestingly, the synthesized CP acts as efficient catalyst for electrocatalytic water splitting. The water oxidation activity of compound 1 exhibits Tafel slope equivalent to 361.48 mV.dec−1 for hydrogen evolution reaction (HER) and 353.53 mV.dec−1 for oxygen evolution reaction (OER) in an alkaline medium while almost similar values of Tafel slope for HER and OER equivalent to 287.33 mV.dec−1 and 289.93 mV.dec−1 respectively in acidic medium. Thus, the compound 1 has excellent efficacy in catalyzing HER and OER in acidic as well as alkaline medium, which is ascribed to its distinctive 3D architecture. [ABSTRACT FROM AUTHOR]

Ferrate, as an internal oxidation modifier, is rarely used in the preparation of magnetic biochar. This research promotes rice shell charcoal modified by K2FeO4 preparation of oxygen-containing groups and ɤ-Fe2O3 magnetic biochar. Magnetic rice husk biochar (MBC) is prepared to adsorb Ni(II) from aqueous solutions. The effects of various parameters on the adsorption of Ni(II) by MBC have been studied, and the results show that MBC has an excellent adsorption capacity for Ni(II). At 25 °C and pH 7.0, the removal rate of Ni(II) reaches 96.1% within 24 h at an adsorbent dose of 0.5 g/L when the initial Ni(II) concentration is 20 mg/L. The kinetic model conforms to the pseudo-second-order kinetic model and the intra-particle diffusion model within 36 h. Moreover, the adsorption data were successfully reproduced by the Langmuir isotherm, and the maximum adsorption capacity is 42.69 mg/g. The adsorption data conform to the D-R model, and the calculated average adsorption free energy is 41.03 kJ/mol, indicating that the adsorption process is mainly chemical adsorption. Thermodynamic study indicates that the endothermic adsorption process is spontaneous and can be promoted by the increase in temperature. This study was expected to provide a reference and theoretical basis for the treatment of Ni(II)-containing wastewater using modified rice husk biochar. [ABSTRACT FROM AUTHOR]

This study focuses on the efficient removal of Ni(II) from spent lithium-ion batteries (LIBs) to support environmental conservation and sustainable resource management. A composite material, known as molecular sieve (MS)-based metal–organic framework (MOF) composites (MMCs), consisting of a synthesized MS matrix with integrated MOFs, was developed for the adsorption of Ni(II). The structural and performance characteristics of the MMCs were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and N2 adsorption–desorption isotherms (BET). Batch adsorption experiments were conducted to assess the Ni(II) adsorption performance of the MMCs. The results revealed that, under conditions of pH 8 and a temperature of 298 K, the MMCs achieved near-equilibrium Ni(II) adsorption within 6 h, with a maximum theoretical adsorption capacity of 204.1 mg/g. Further analysis of the adsorption data confirmed that the adsorption process followed a pseudo-second-order kinetic model and Langmuir isotherm model, indicating a spontaneous, endothermic chemical adsorption mechanism. Importantly, the MMCs exhibited superior Ni(II) adsorption compared to the MS. This study provides valuable insights into the effective recovery and recycling of Ni(II) from spent LIBs, emphasizing its significance for environmental sustainability and resource circularity. [ABSTRACT FROM AUTHOR]

In our earlier paper, authors have been reported that Ni(II) resistant Saccharomyces cerevisiae AJ208 was developed to remove the elevated level of Ni(II) concentration, and 70% removal was observed concerning the initial Ni(II) concentration of 3000 mg/L. This article aims to screen the facilitated Ni(II) removal after optimizing carbon-nitrogen and macro-micro elements as nutritional supplements into fermentation media from an aqueous solution. In the fermentation media, the synthetic carbon-nitrogen sources and macro-micro elements were added and optimized to obtain better Ni(II) percentage removal from the aqueous solution by using the Ni(II) resistant strain of S. cerevisiae AJ208. As newly optimized carbon-nitrogen sources, sucrose, and ammonium chloride collectively provide 75% Ni(II) removal. The macro-micro elements, magnesium sulfate, potassium dihydrogen phosphate, potassium chloride, calcium chloride, ferric sulfate, and zinc sulfate, positively impacted S. cerevisiae AJ208 growth and fermentation. After optimization, it provided 85% Ni(II) removal. The adsorbent was also characterized with SEM-EDAX, Raman, and FTIR analysis. The adsorption study shows a striking enhancement in Ni(II) removal after adding mentioned nutritive elements. The genetic algorithm is also successfully applied using the data acquired from the experiment. [ABSTRACT FROM AUTHOR]

In this work, a new Ni(II) unsymmetrical Schiff-base complex, Ni(salenac), was successfully synthesized and immobilized into three-dimensional (3D) mesoporous silica KIT-6 (Korean Institute of Technology No. 6). The novel composite KIT-6-pr-NH2-Ni(salenac) was characterized by various techniques and utilized to selectively oxidize different aromatic and aliphatic sulfides to the corresponding sulfoxides with yields of 80–95% by using hydrogen peroxide (30% H2O2) as an environmentally friendly oxidant in ethanol solution at 25 °C. This oxidizing system allowed the chemoselective oxidation of sulfides containing other functional groups. The results showed that the OH and C=C groups of the compounds such as 2-hydroxyethyl phenyl sulfide and allyl methyl sulfide remained intact during sulfide oxidation. The catalyst was stable in the reaction conditions, and could be recused at least five times without significant decline in catalytic activity. Moreover, Fourier transform infrared (FTIR) spectrum of the recovered catalyst matches that of the fresh catalyst, and the catalyst structure remains unchanged after recovery. [ABSTRACT FROM AUTHOR]

In the context of carbon neutrality, promoting resource utilization of industrial alkali lignin addressing heavy metal pollution is crucial for China's pollution alleviation and carbon reduction. Microwave pyrolysis produced functionalized biochar from industrial alkali lignin for Ni(II) adsorption. LB400 achieved 343.15 mg g−1 saturated adsorption capacity in 30 min. Pseudo-second-order kinetic and Temkin isotherm models accurately described the adsorption, which was endothermic and spontaneous (ΔGϴ < 0, ΔHϴ > 0). Quantitative analysis revealed that both dissolved substances and carbon skeleton from biochar contributed to adsorption, with the former predominates (93.76%), including mineral precipitation NiCO3 (Qp) and adsorption of dissolved organic matter (QDOM). Surface complexation (Qc) and ion exchange (Qi) on the carbon skeleton accounted for 6.3%. Higher biochar preparation temperature reduced Ni(II) adsorption by dissolved substances. Overall, biochar which comes from the advantageous disposal of industrial lignin effectively removes Ni(II) contamination, encouraging ecologically sound treatment of heavy metal pollution and sustainable resource utilization. [ABSTRACT FROM AUTHOR]

In this study, nanoparticles of calcium oxide (CaO-NPs) were prepared via the sol-gel technique and introduced as a highly efficient adsorbent for removing Ni(II) from aqueous media. The prepared adsorbent was characterised via SEM, TEM, FTIR, XRD, and TGA. The pHzpc and surface area were also determined. XRD pattern exposed a polycrystalline nature of the adsorbent. SEM analysis showed that the adsorbent possesses enhanced surface porosity highlighting its potential capacity for adsorption. TEM analysis confirmed the crystallisation of adsorbent with a simple cubic structure. The FTIR spectrum displayed that the adsorbent surface comprises mostly (–OH and C=O) groups which are principally accountable for the adsorption of Ni(II). A series of batch adsorption experiments were done to study the effect of several parameters as pH, adsorbent dose, time of contact, initial concentration of adsorbate, temperature, ionic strength, and presence of interfering ions on the removal of Ni(II) ions from aqueous solutions using CaO-NPs. Maximum removal was obtained with 200 mg of adsorbent after 90 min contact time at pH 7 and 25°C as optimal conditions. The adsorption process was fitted well with Langmuir isotherm model and pseudo-second-order kinetic model, showing that the adsorption of Ni(II) ions on CaO-NPs was monolayer coverage with 166.67 mg/g capacity of adsorption. Thermodynamic studies revealed a spontaneous and endothermic adsorption process. The regeneration study using Na2EDTA indicated that the prepared adsorbent has a high renewal potential without notable loss in its performance. Moreover, the prepared adsorbent proved its good applicability and performance by successful application of the suggested procedure for the recovery of Ni(II) added to some real water samples. Accordingly, the obtained results showed that CaO-NPs can rapidly and efficiently remove Ni(II) from aqueous solutions. Also, CaO-NPs adsorbent is eco-friendly, easy to produce, cost-effective, non-toxic, and with good adsorption-desorption capacity. Therefore, this study will contribute to ecological cleaning and wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract The ligand N-{[(phenyl amino) thioxomethyl] hydrazino carbonyl methyl} trimethyl ammonium chloride (PTHAC) was prepared by the refluxing phenyl isothiocyanate and Girard-T (trimethyl ammonium-acethydrazide) in a molar ratio (1:1). The metal complexes derived from NiCl2.6H2O, CuCl2.2H2O and Co(CH3COO)2.6H2O were synthesized and purified. The PTHAC and its Cu(II), Co(II), and Ni(II) metal complexes(1–3) were characterized using a variety of various instrumental performances such as elemental analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass) and thermal analysis (TGA and DTG).The results of element analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass), and thermal (TGA and DTA) analyses provide the structures of the produced ligand and its (1–3) complexes. According to the spectroscopic results, PTHAC acts as an O, N and S tridentate donor, creating a mononuclear complex with copper(II), cobalt(II), and nickel(II) ions with an octahedral geometry. All of the atomic properties, including bond lengths, bond angles, HOMO, LUMO, dipole moments, and charges, have been determined. The cytotoxic activities of the PTHAC and the produced (1–3) complexes against breast carcinoma cells have been studied and correlated to the molecular modeling. When compared to the free ligand, CoII-L, and NiII-L, the CuII-L complex inhibits breast cancer cell growth more effectively. Furthermore, the PTHAC ligand was successfully applied for separation via flotation and spectrophotometric determination of Co(II) in several natural water, certified ore and pharmaceutical samples using oleic acid surfactant (HOL). At pH 6.5, PTHAC reacted with Co(II) to create a dark green (1:1) Co(II):PTHAC complex that was floated significantly using oleic acid (HOL) surfactant. The different experimental variable affecting the separation procedure e.g. pH, concentration of Co(II), HOL, PTHAC, temperature etc.…, were investigated. Co(II) had a linear range of (0.1–7.0) mgL−1. In the aqueous and scum layers, the molar absorptivities for the coloured complex are 0.14 × 104 and 0.16 × 105Lmol−1 cm−1, respectively. The LOD was 0.04 mgL−1, which is related to Sandell sensitivity of 3.7 × 10−3 µg cm−2 with a preconcentration factor of 200 and a RSD, % (n = 5) less than 4.2%. In addition, the mechanisms involved in the process of coordination of PTHAC with Cu(II), Co(II) and Ni(II) and the mechanism involved in the process of flotation of the PTHAC-Co(II) complex using HOL surfactant were elucidated.

This study focuses on the efficient removal of Ni(II) from spent lithium-ion batteries (LIBs) to support environmental conservation and sustainable resource management. A composite material, known as molecular sieve (MS)-based metal–organic framework (MOF) composites (MMCs), consisting of a synthesized MS matrix with integrated MOFs, was developed for the adsorption of Ni(II). The structural and performance characteristics of the MMCs were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and N2 adsorption–desorption isotherms (BET). Batch adsorption experiments were conducted to assess the Ni(II) adsorption performance of the MMCs. The results revealed that, under conditions of pH 8 and a temperature of 298 K, the MMCs achieved near-equilibrium Ni(II) adsorption within 6 h, with a maximum theoretical adsorption capacity of 204.1 mg/g. Further analysis of the adsorption data confirmed that the adsorption process followed a pseudo-second-order kinetic model and Langmuir isotherm model, indicating a spontaneous, endothermic chemical adsorption mechanism. Importantly, the MMCs exhibited superior Ni(II) adsorption compared to the MS. This study provides valuable insights into the effective recovery and recycling of Ni(II) from spent LIBs, emphasizing its significance for environmental sustainability and resource circularity.

The ligand N-{[(phenyl amino) thioxomethyl] hydrazino carbonyl methyl} trimethyl ammonium chloride (PTHAC) was prepared by the refluxing phenyl isothiocyanate and Girard-T (trimethyl ammonium-acethydrazide) in a molar ratio (1:1). The metal complexes derived from NiCl2.6H2O, CuCl2.2H2O and Co(CH3COO)2.6H2O were synthesized and purified. The PTHAC and its Cu(II), Co(II), and Ni(II) metal complexes(1–3) were characterized using a variety of various instrumental performances such as elemental analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass) and thermal analysis (TGA and DTG).The results of element analysis, magnetic moment, spectra (IR, UV–Vis, 1H NMR, mass), and thermal (TGA and DTA) analyses provide the structures of the produced ligand and its (1–3) complexes. According to the spectroscopic results, PTHAC acts as an O, N and S tridentate donor, creating a mononuclear complex with copper(II), cobalt(II), and nickel(II) ions with an octahedral geometry. All of the atomic properties, including bond lengths, bond angles, HOMO, LUMO, dipole moments, and charges, have been determined. The cytotoxic activities of the PTHAC and the produced (1–3) complexes against breast carcinoma cells have been studied and correlated to the molecular modeling. When compared to the free ligand, CoII-L, and NiII-L, the CuII-L complex inhibits breast cancer cell growth more effectively. Furthermore, the PTHAC ligand was successfully applied for separation via flotation and spectrophotometric determination of Co(II) in several natural water, certified ore and pharmaceutical samples using oleic acid surfactant (HOL). At pH 6.5, PTHAC reacted with Co(II) to create a dark green (1:1) Co(II):PTHAC complex that was floated significantly using oleic acid (HOL) surfactant. The different experimental variable affecting the separation procedure e.g. pH, concentration of Co(II), HOL, PTHAC, temperature etc...., were investigated. Co(II) had a linear range of (0.1–7.0) mgL−1. In the aqueous and scum layers, the molar absorptivities for the coloured complex are 0.14 × 104 and 0.16 × 105Lmol−1 cm−1, respectively. The LOD was 0.04 mgL−1, which is related to Sandell sensitivity of 3.7 × 10−3 µg cm−2 with a preconcentration factor of 200 and a RSD, % (n = 5) less than 4.2%. In addition, the mechanisms involved in the process of coordination of PTHAC with Cu(II), Co(II) and Ni(II) and the mechanism involved in the process of flotation of the PTHAC-Co(II) complex using HOL surfactant were elucidated. [ABSTRACT FROM AUTHOR]

The kinetics and mechanism of the electrochemical redox reaction of 3-(3,5-dimethilpirazole-1-yl)-6-R-1,2,4,5-tetrazines and their Cu(II), Co(II), and Ni(II) complexes were studied by voltammetry on glassy carbon electrodes in aqueous acetonitrile. The characteristics of electrode processes in the studied systems were determined. [ABSTRACT FROM AUTHOR]

The salen-type Ni(II) and Fe(III) complexes were successfully syntheses by using Schiff base ligand [E]-2,2'-((pentane-1,3-diylbis(azanylylidene))bis(ethan-1-yl-1-ylidene))bis(naphthalen-1-ol) (L1) and its derivatives (L2) and (L3). Due to their chelating properties and ability to coordinate with a wide range of transition metal ions of different oxidation states, they are considered an important family of organic compounds. The structure of the metal complexes was elucidated by different spectral techniques (FT-IR, 1H NMR, mass spectrometry, UV–visible, powder X-ray diffraction, DGA-TGA, and ESR). The powder X-ray diffraction data revealed that Ni(II) complexes are arranged in a triclinic system while Fe(III) complexes are in a monoclinic system with space group P1. TGA-DTA study suggests that the Ni(II) ion does coordinate with the N2O2 Schiff base ligands with coordination number 4. Also, the Fe(III) ion does coordinate with the N2O2 Schiff base ligands with coordination number 6. The Ni(II) complex exhibits the square planar geometry with unpaired electron lying in the dx2-y2 orbital. The EPR spectra of Fe(III) complexes may suggest an octahedral structure around the Fe(III) ion. The antibacterial activity was tested against different pathogens and confirmed that the presence of the –I and –NO2 group with N2O2 donor Schiff bases ligand are responsible for strongly inhibiting bacterial growth of metal complexes. The Ni(II) complexes showed higher potency antioxidant activity, indicating that the Ni (II) complexes exhibited more prominent antioxidant activity than the Fe (III) complexes. [ABSTRACT FROM AUTHOR]

The purpose of this research work is to investigate the sorption characteristic of Polypyrrole/Fe3O4 (PPy/Fe3O4) nanocomposite (NC) for the removal of Ni(II) ions from aqueous solutions. The adsorbent was characterized using SEM, FTIR, and XRD. The SEM micrographs show the formation of PPy/Fe3O4 NC within 32–41 nm in size which has been homogeneously dispersed. The sorption of Ni(II) ions by a batch method was carried out and the optimum conditions were investigated. To determine the optimal conditions for adsorption, the effect of important parameters such as pH, contact time, initial concentration of Ni(II), amount of adsorbent, and temperature were investigated. Two models, Lagergren and pseudo-second order have been tested to track the kinetics of the removal process. Adherence of the adsorption process from pseudo-second-order kinetics and chemical adsorption was proved. The Langmuir and Freundlich were employed for the treatment of the equilibrium adsorption data and yielded a good fit with the Freundlich isotherm model. The PPy Fe3O4 NC has considerable Langmuir adsorption capacity to Ni(II) removal 250.0 mg/g. The adsorption process was exothermic with a negative value of ΔH° (− 21.9 kJ/mol) and spontaneous in nature (ΔG° = − 7.03 kJ/mol). The results have established the good potentiality of the Polypyrrole/Fe3O4 NC to remove Ni(II) from aqueous solutions. [ABSTRACT FROM AUTHOR]

This study presents a direct multicomponent analysis method using UV-Vis spectrophotometry to determine Cu(II), Fe(III), and Ni(II) ion content without prior complexation or separation. Single and multivariate regression was used to predict metal ion content, and the resulting model was trained and validated using a dataset of 25 multi-component samples. The mean recoveries for Cu(II), Fe(III), and Ni(II) using linear and ridge regression based only on absorbance at 805 nm were 99.97% and 101.6%, 95.42% and 95.65%, and 99.43% and 99.99%, respectively, for the 20% test data. The mean recoveries for Cu(II), Fe(III), and Ni(II) using linear and ridge regression based only on absorbance at 805 nm were 92.27% and 95.03%, 125.3% and 124.11%, and 104.15% and 105.52%, respectively, for the test solution outside of the training data. These results demonstrate the effectiveness of the multivariate UV-Vis spectrophotometric method for the simultaneous determination of Cu(II) and Ni(II) in multicomponent samples, which meets the analysis standard and can be successfully applied. Finally, the study sheds light on the influence of spectral interference on the accuracy of regression models. It highlights the importance of carefully selecting the wavelengths used as predictors in such models. This can have significant implications for developing and validating analytical methods, particularly in cases where multiple analytes were present in a sample.

In this study, we present the synthesis of a novel peptide-based magnetogel obtained through the encapsulation of γ-Fe2O3-polyacrylic acid (PAA) nanoparticles (γ-Fe2O3NPs) into a hydrogel matrix, used for enhancing the ability of the hydrogel to remove Cr(III), Co(II), and Ni(II) pollutants from water. Fmoc-Phe (Fluorenylmethoxycarbonyl-Phenylalanine) and diphenylalanine (Phe2) were used as starting reagents for the hydrogelator (Fmoc-Phe3) synthesis via an enzymatic method. The PAA-coated magnetic nanoparticles were synthesized in a separate step, using the co-precipitation method, and encapsulated into the peptide-based hydrogel. The resulting organic/inorganic hybrid system (γ-Fe2O3NPs-peptide) was characterized with different techniques, including FT-IR, Raman, UV-Vis, DLS, ζ-potential, XPS, FESEM-EDS, swelling ability tests, and rheology. Regarding the application in heavy metals removal from aqueous solutions, the behavior of the obtained magnetogel was compared to its precursors and the effect of the magnetic field was assessed. Four different systems were studied for the separation of heavy metal ions from aqueous solutions, including (1) γ-Fe2O3NPs stabilized with PAA, (γ-Fe2O3NPs); (2) Fmoc-Phe3 hydrogel (HG); (3) γ-Fe2O3NPs embedded in peptide magnetogel (γ-Fe2O3NPs@HG); and (4) γ-Fe2O3NPs@HG in the presence of an external magnetic field. To quantify the removal efficiency of these four model systems, the UV-Vis technique was employed as a fast, cheap, and versatile method. The results demonstrate that both Fmoc-Phe3 hydrogel and γ-Fe2O3NPs peptide magnetogel can efficiently remove all the tested pollutants from water. Interestingly, due to the presence of magnetic γ-Fe2O3NPs inside the hydrogel, the removal efficiency can be enhanced by applying an external magnetic field. The proposed magnetogel represents a smart multifunctional nanosystem with improved absorption efficiency and synergic effect upon applying an external magnetic field. These results are promising for potential environmental applications of γ-Fe2O3NPs-peptide magnetogels to the removal of pollutants from aqueous media. [ABSTRACT FROM AUTHOR]

The two complexes, [Ni(DPPT)2](NO3)2*1.5H2O (1) and [Ni(DPPT)(NO3)Cl].EtOH (2), were synthesized using the self-assembly of (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine (DPPT) with Ni(NO3)2*6H2O in the absence and presence of NiCl2*6H2O, respectively. In both cases, the neutral tridentate DPPT ligand is found coordinated to the Ni(II) via three N-atoms from the hydrazone, pyridine and s-triazine rings. Hence, the homoleptic complex 1 has a NiN6 hexa-coordination environment while two NO3− are counter anions in addition to one-and-a-half crystallized hydration water molecules are found acting as an outer sphere. The heteroleptic complex 2 has a NiN3O2Cl coordination sphere where the coordination environment of the Ni(II) is completed by one bidentate nitrate and one chloride ion leading to a neutral inner sphere while the outer sphere contains one crystallized ethanol molecule. Both complexes have distorted octahedral coordination environments around the Ni(II) ion. Using Hirshfeld analysis, the intermolecular contacts H...H and O...H in 1 and the Cl...H, O...H, N...H, H...H, C...H and C...C in 2 are found to be the most important for crystal stability. The antimicrobial activity of complexes 1 and 2 was assessed against different bacterial and fungal strains, and the results were compared with the free ligand as well as the antibacterial (Gentamycin) and antifungal (Ketoconazole) positive controls. Both Ni(II) complexes are better antibacterial and antifungal agents than the free ligand. Interestingly, both Ni(II) complexes have similar antifungal activity against C. albicans compared to Ketoconazole. [ABSTRACT FROM AUTHOR]

Using density functional theory (DFT) B3PW91/TZVP, M06/TZVP, and OPBE/TZVP chemistry models and the Gaussian09 program, a quantum-chemical calculation of geometric and thermodynamic parameters of Ni(II), Cu(II), and Zn(II) macrotetracyclic chelates, with (NNNN)-coordination of ligand donor centers arising during template synthesis between the indicated ions of 3d elements, thiocarbohydrazide H2N–HN–C(=S)–NH–NH2 and diacetyl Me–C(=O)–C(=O)–Me, in gelatin-immobilized matrix implants was performed. The key bond lengths and bond angles in these coordination compounds are provided, and it is noted that in all these complexes the MN4 chelate sites, the grouping of N4 atoms bonded to the M atom, and the five-membered and six-membered metal chelate rings are practically coplanar. NBO analysis of these compounds was carried out, on the basis of which it was shown that all these complexes, in full accordance with theoretical expectations, are low-spin complexes. The standard thermodynamic characteristics of the template reactions for the formation of the above complexes are also presented. Good agreement between the data obtained using the above DFT levels is noted. [ABSTRACT FROM AUTHOR]

This paper presents the expansion of an optical, chemical sensor that can rapidly and reliably detect, quantify, and remove Ni(II) ions in oil products and electroplating wastewater sources. The sensor is based on mesoporous silica nanospheres (MSNs) that have an extraordinary surface area, uniform surface morphology, and capacious porosity, making them an excellent substrate for the anchoring of the chromoionophoic probe,3′‐{(1E,1′ E)‐[(4‐chloro‐1,2 phenylene)bis (azaneylylidene)]‐bis(methaneylylidene)}bis(2‐hydroxybenzoic acid) (CPAMHP). The CPAMHP probe is highly selective and sensitive to Ni(II), enabling it to be used in naked‐eye colorimetric recognition of Ni(II) ions. The MSNs provide several accessible exhibited sites for uniform anchoring of CPAMHP probe molecules, making it a viable chemical sensor even with the use of naked‐eye sensing. The surface characters and structural analysis of the MSNs and CPAMHP sensor samples were examined using various techniques. The CPAMHP probe‐anchored MSNs exhibit a clear and vivid color shift from pale yellow to green upon exposure to various concentrations of Ni(II) ions, with a reaction time down to approximately 1 minute. Furthermore, the MSNs can serve as a base to retrieve extremely trace amounts of Ni(II) ions, making the CPAMHP sensor a dual‐functional device. The calculated limit of recognition for Ni(II) ions using the fabricated CPAMHP sensor samples is 0.318 ppb (5.43 × 10−9 M). The results suggest that the proposed sensor is a promising tool for the sensitive and reliable detection of Ni(II) ions in petroleum products and for removing Ni(II) ions in electroplating wastewater; the data indicate an excellent removal of Ni (II) up to 96.8%, highlighting the high accuracy and precision of our CPAMHP sensor. [ABSTRACT FROM AUTHOR]

Zero-valent iron nanoparticles (nZVI) were successfully synthesized by metal salt reduction method using cinnamon as a reductor agent. Particle size analysis showed that the most optimum composition of FeSO4 and polyphenols was at a ratio of 4:1, resulting in Dv(10), Dv(50), and Dv(90) values of 23.7 nm, 44.6 nm, and 178 nm, respectively. Scanning electron microscopy showed that nZVI was spherical and agglomerated. X-ray diffraction pattern showed a peak at 45.03˚ that corresponds to nZVI. The batch test showed that nZVI has Ni(II) and Cr(VI) adsorption activity of 95.58% Ni and 64.29%, respectively.

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to synthesize chitosan crosslinked by sodium tripolyphosphate with different concentrations and optimize it for Ni(II) adsorption in a batch adsorption system. The BET analysis and the solubility/swelling test showed that as the crosslinking degree increased, the surface area and total pore volume decreased while the physicochemical properties improved. The effect of the initial pH and temperature on the adsorption of Ni(II) was studied in a batch adsorption system, and thermodynamic parameters were calculated. In order to enhance the adsorption capacity of crosslinked chitosan, Response Surface Methodology (RSM) was employed to establish a correlation between two independent experimental factors, namely pH and crosslinking degree, and the Ni(II) adsorption capacity. By changing these factors, the aim was to optimize the adsorption capacity of crosslinked chitosan. The constructed model was well-aligned with the experimental data with an R2 = 96.05%. According to the model, an adsorption capacity of 31.94 mg/g could be achieved at a pH of 7.21 and a crosslinking degree of 2.93% (w/v). Among isotherm models investigated, the Langmuir model was found to be more appropriate for studying Ni(II) adsorption with maximum adsorption capacity in the order of chitosan beads> crosslinked chitosan beads. The mechanism of adsorption and crosslinking reaction was also investigated using FT-IR and SEM-EDS techniques, implying that the amine groups were the primary sites for metal ions uptake as well as crosslinking reaction. A mixture of NaCl and H2SO4 could release the sorbed Ni(II) ions from STPP-CB5% with a recovery of 83% after one sorption-desorption cycle.

This review focuses on some interesting and recent applications of transition metals towards the complexation of thiosemicarbazides, thiocarbohydrazides, and their corresponding carbazones. We started the review with a description of the chosen five metals, including Cu[Cu(I), Cu(II], Co(II), Ni(II), Pd(II), and Ag(I) and their electronic configurations. The stability of the assigned complexes was also discussed. We shed light on different routes describing the synthesis of these ligands. We also reported on different examples of the synthesis of Cu(I), Cu(II), Co(II), Ni(II), Ag(I), and Pd(II) of thiosemicarbazide and thiocarbohydrazide complexes (until 2022). This review also deals with a summary of the fruitful use of metal complexes of thiosemicarbazones and thiocarbazones ligands in the field of catalysis. Finally, this recent review focuses on the applications of these complexes related to their biological importance. [ABSTRACT FROM AUTHOR]

A Schiff base, 3-Hydroxy-4-(3-hydroxy benzylidene amino) benzoic acid was synthesized from the corresponding starting ketone, 3-Hydroxy benzaldehyde and amine, 3-hydroxy 4-amino benzoic acid by condensation reaction. Further, the metal complexes of the Schiff base with Ni(II) and Zn(II) were synthesized. These Schiff base and its Ni(II) and Zn(II) metal complexes were characterized by spectral techniques like FT-IR, ¹H NMR and 13C NMR spectroscopy. The synthesized compounds were evaluated for their antibacterial activity against Gram positive and negative bacteria like Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The anti-fungal activities were also studied for Candida albicans, Candida parapsilosis. The Zn(II) metal complex exhibited the good antibacterial and antifungal activity among the all prepared compounds. [ABSTRACT FROM AUTHOR]

The effects of NO3− and/or NH4+, and nickel on the growth and photosynthesis-respiration metabolism of Botryococcus braunii were analyzed. NO3−, NH4+ and Ni(II) removal capacity are described in terms of metabolic and non-metabolic processes. Results demonstrate that B. braunii can live in a pH range from 3 to 9. The total productivity (P) and the productivity of the growth phase (Pv) are higher (≈ 58 and 61 mg L−1 day−1, respectively) when the medium contains NH4+, than when it contains NO3− (≈ 45 and 51 mg L −1 day−1, respectively). NH4+ consumption results in a decrease of the pH of the medium from 7 to 3. Botryococcus braunii reverse the acidic conditions of the medium when NO3− is metabolized (pH from 5 to 8–8.5). Ni(II)-specific removal is mainly due to adsorption and increases along with pH and initial metal concentration. The Hill model best describes the adsorption experimental data. The stoichiometric correlations between H+ desorption and nickel adsorption were 1:5, 1:3 and 1:2 for pH values of 5, 6 and 7, respectively. The present work is a new contribution on the biotechnological potential of B. braunii to live and grow at different pH and to remove NO3−, NH4+, and Ni(II) by metabolic and non-metabolic pathways. [ABSTRACT FROM AUTHOR]

The emergence of new biotechnologies has increased interest in the study of the impact of environmental contamination on microbial communities, particularly in relation to the potential benefits that stress-adapted microorganisms offer in environmental protection, industrial ecology, and mineral and waste processing. This study aimed to compare the bioaccumulation abilities of recently isolated microscopic fungi belonging to the genera Aspergillus, Phoma, Cystobasidium, Cladosporium and Exophiala. These fungi were isolated from a site contaminated with both toxic metals and organic pollutants. The study monitored the bioaccumulation of selected toxic metal ions (Cu(II), Zn(II), Ni(II), Cr(III), Pb(II)), as well as pH changes, over a 30-day of biomass growth. The medium containing Pb(II) exhibited a statistically significant pH change during the 30-day accumulation period (Mann-Whitney U Test, p < 0.05). These findings provide valuable insights for the potential industrial application of microscopic fungi in bioaccumulation processes.

A spectrophotometric flow-based method for the determination of nickel in recreational waters is proposed. In this scenario, the strategy was to devise a miniaturized and automatic system based on sequential injection analysis, aiming for an expeditious, real-time and low-cost determination. For the spectrophotometric determination, dimethylglyoxime was used as color reagent due to its selectivity for nickel. Considering the expected low concentration and low sensitivity of the coloured reaction, a long pathlength flow cell was used to increase the sensitivity. The potential interference of metal ions commonly present in freshwaters was assessed and no significant differences (

Agriculture, industry, urbanization, and population growth lead to the spread of countless pollutants to the environment. Environmental pollution is one of the biggest problems faced by humanity. There are numerous chemicals (heavy metals, dyes, detergents, toxic compounds with aromatic rings, etc.) causing environmental pollution. For example, the use of heavy metals in industrial, medical, and technological sectors causes negative effects on the environment and human health. Chemical methods are not found to be effective for low concentrations of heavy metal pollution, and can also cause the formation of toxic sludge, which is itself a pollutant. Biological methods are preferred instead of chemical methods in heavy metal removal. In the biological treatment methods, microorganisms capable of bioremediation capacity are used. In the current study, bioremediation of Ni(II) by thermophile Cyanobacterium aponinum was investigated. The optimum pH was 9 corresponding to the highest heavy metal bioremoval capacity. The efficiency of bioremediation ranged from 32 to 83% in samples with Ni(II). C. aponinum tolerated all the temperatures (25, 35, and 45°C) tested in the study in the media with Ni(II). In addition, the highest bioremediation capacity was found at 45°C. The increment of biomass concentration affected bioremoval efficiencies positively. In samples with 40% (v/v) biomass, the highest yield was 83% in media with 15.9 mg/L Ni(II) at 45°C. The maximum specific heavy metal removal (qmax) had its highest value as 11.8 mg/g in samples with 14.6 mg/L Ni(II) at 45°C. There are apparently no other studies investigating heavy metal bioremediation by thermophile C. aponinum under different environmental conditions. The data showed that C. aponinum is suitable for effective treatment processes of wastewaters, including Ni(II). [ABSTRACT FROM AUTHOR]

Objective: Chemotherapy is one of the most effective and widely used treatment types for breast cancer. The Ni(II) proline dithiocarbamate (Ni(II)ProDtc) complex has been synthesized as a potential anticancer agent with minimal systemic toxicity. The dithiocarbamate ligand, combined with the amino acid proline, holds promise as a radio chemotherapeutic target agent in tumors. The anticancer activity of a Ni(II) complex compound with a proline dithiocarbamate ligand was tested on the MCF-7 breast cancer cell line as part of a study on essential metal-based therapeutics., Methods: Molecular docking studies identified the active sites for the estradiol-estrogen receptor-α protein. The Ni(II)ProDtc complex was synthesized and characterized using melting point analysis, conductivity measurements, UV-Vis spectroscopy, and FT-IR spectroscopy. The cytotoxicity of the complex was evaluated in vitro using the MCF-7 breast cancer cell line., Results: The UV-Vis spectrum at 246 nm indicated the π→π* intraligand transition of the CS2 group, while FT-IR analysis revealed peaks at 364-457 cm-1 corresponding to the bonding between Ni and Sulfur (S) and Oxygen (O) from proline. Further, the UV-Vis spectrum displayed bands at 212 and 676 nm, and FT-IR data at 387-691 cm-1, confirming the coordination of the Ni(II) atoms with sulfur, nitrogen, and oxygen in the isoleucine dithiocarbamate ligand. In vitro, cytotoxicity tests revealed that Ni(II)ProDtc induced cell death in the breast cancer cell line, showing significant morphological changes in MCF-7 cancer cells, with an IC50 value of 315.70 µg/mL., Conclusion: The Ni(II)ProDtc complex was successfully synthesized and demonstrates anticancer activity in MCF-7 breast cancer cells, indicating significant potential as an anticancer agent for breast cancer.

Due to their toxicity, Cd(II) and Ni(II) ions in the environment are severe. The hydroxyapatite composite was improved with magnetic MnFe2O4 to remove Cd(II) and Ni(II) ions from an aqueous solution. Hydroxyapatite was extracted from Snakehead (Channa striata) fish bones via alkaline-heat treatment. The hydroxyapatite/MnFe2O4 composite performance was analyzed through XRD, FTIR, SEM-EDS, BET analysis, and VSM, and the results reveal that the hydroxyapatite/MnFe2O4 composite shows good magnetic properties of 21.95 emu/g. The kinetics evaluation confirmed that the pseudo-second-order kinetics model was more suitable to describe the adsorption of Cd(II) and Ni(II) ions by hydroxyapatite/MnFe2O4 composite from the solution. The Langmuir isotherm model was suitable to describe the adsorption process of the Cd(II) and Ni(II) ions, where the adsorption capacities for Cd(II) and Ni(II) are 54.3 and 47.4 mg/g, respectively. Desorption of Cd(II) and Ni(II) ions from hydroxyapatite/MnFe2O4 composite using NaCl as the eluent was more effective than EDTA. The findings of this study indicate that hydroxyapatite/MnFe2O4 can reduce Cd(II) and Ni(II) ions in wastewater so that it can recover natural resources.

The two complexes, [Ni(DPPT)2](NO3)2*1.5H2O (1) and [Ni(DPPT)(NO3)Cl].EtOH (2), were synthesized using the self-assembly of (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine (DPPT) with Ni(NO3)2*6H2O in the absence and presence of NiCl2*6H2O, respectively. In both cases, the neutral tridentate DPPT ligand is found coordinated to the Ni(II) via three N-atoms from the hydrazone, pyridine and s-triazine rings. Hence, the homoleptic complex 1 has a NiN6 hexa-coordination environment while two NO3− are counter anions in addition to one-and-a-half crystallized hydration water molecules are found acting as an outer sphere. The heteroleptic complex 2 has a NiN3O2Cl coordination sphere where the coordination environment of the Ni(II) is completed by one bidentate nitrate and one chloride ion leading to a neutral inner sphere while the outer sphere contains one crystallized ethanol molecule. Both complexes have distorted octahedral coordination environments around the Ni(II) ion. Using Hirshfeld analysis, the intermolecular contacts H…H and O…H in 1 and the Cl…H, O…H, N…H, H…H, C…H and C…C in 2 are found to be the most important for crystal stability. The antimicrobial activity of complexes 1 and 2 was assessed against different bacterial and fungal strains, and the results were compared with the free ligand as well as the antibacterial (Gentamycin) and antifungal (Ketoconazole) positive controls. Both Ni(II) complexes are better antibacterial and antifungal agents than the free ligand. Interestingly, both Ni(II) complexes have similar antifungal activity against C. albicans compared to Ketoconazole.

Batch experiments were used to study the interaction mechanism of Ni(II) with biochar as a function of solution pH, contact time, initial concentrations, reaction temperature, and the addition of humic compounds. The results indicate that Ni(II) can be interacted with biochar by a compound mechanism under different environmental conditions. It is suggested that outer-sphere surface complexes at low pH are transformed into inner-sphere surface complexes and surface precipitates are formed at pH 8.89 or 10.18. The combined macroscopic and microscopic insights provide additional details regarding the mobility, fate, and risk of Ni(II) in a practical aquatic environment, as well as the natural purification of metals in ecological environments. [ABSTRACT FROM AUTHOR]

Using density functional theory (DFT) B3PW91/TZVP, M06/TZVP, and OPBE/TZVP chemistry models and the Gaussian09 program, a quantum-chemical calculation of geometric and thermodynamic parameters of Ni(II), Cu(II), and Zn(II) macrotetracyclic chelates, with (NNNN)-coordination of ligand donor centers arising during template synthesis between the indicated ions of 3d elements, thiocarbohydrazide H2N–HN–C(=S)–NH–NH2 and diacetyl Me–C(=O)–C(=O)–Me, in gelatin-immobilized matrix implants was performed. The key bond lengths and bond angles in these coordination compounds are provided, and it is noted that in all these complexes the MN4 chelate sites, the grouping of N4 atoms bonded to the M atom, and the five-membered and six-membered metal chelate rings are practically coplanar. NBO analysis of these compounds was carried out, on the basis of which it was shown that all these complexes, in full accordance with theoretical expectations, are low-spin complexes. The standard thermodynamic characteristics of the template reactions for the formation of the above complexes are also presented. Good agreement between the data obtained using the above DFT levels is noted.

[Display omitted] • S@AZVI with elevated Fe0 content was synthesized via post-sulfidation. • The FeS shell enhanced electron transport within the amorphous Fe0 core. • The ideal thickness of FeS ensured optimal reactivity. • Cr(VI) and Ni(II) were rapidly and synchronously removed from real wastewater. As one category of promising and efficacious purification material toward environmentally harmful heavy metals, sulfidated amorphous zero-valent Iron (S@AZVI) exhibits unparalleled removal performance. Due to the disruptive crystal growth however, the irreversible loss of Fe0 component during conventional synthesis route poses a substantial hindrance to its industrial application. To address this, we propose a post-sulfidation strategy to hinder the transformation of Fe0 by altering the shell composition of AZVI from Fe 2 O 3 to FeS, which maintains a remarkable Fe0 content up to 75.7 % over finally obtained S@AZVI, far higher than the material obtained through the one-step sulfidation. Attributing to the synergy of FeS shell and substantial Fe0, S@AZVI demonstrates impressive performance as the lowest free corrosion potential (−1.050 V) and work function (4.058 eV), and subsequently exhibits a notable enhancement in the removal efficiency of Cr(VI) and Ni(II), surpassing AZVI by 1.8 and 2.0 times, respectively. Results reveal that the adsorption, reduction, and coprecipitation constitute the mechanisms governing the removal of Cr(VI) and Ni(II). In practical electroplating wastewater experiments, S@AZVI effectively removes Cr(VI) and Ni(II) within a 60-min timeframe, meeting established emission standards. These findings provide valuable insights for future AZVI material synthesis for heavy metal elimination. [ABSTRACT FROM AUTHOR]

Ekstraksi asam humat dari kotoran kuda telah dilakukan dengan prosedur standar International Humic Substance Society (IHSS) di bawah atmosfer udara. Penelitian ini dilakukan untuk memanfaatkan asam humat kotoran kuda (AHKK) sebagai adsorben limbah logam Ni (II). Dugaan awal adanya Asam Humat dalam kotoran kuda dikarenakan kandungan lignin di dalamnya. Persentase ekstraksi asam humat murni dari kotoran kuda mencapai 0,4%. Interaksi AHKK dengan logam Ni(II) dilakukan dalam larutan. Aspek adsorpsi yang dipelajari meliputi pengaruh pH, waktu kontak, kinetika, kapasitas adsorpsi, dan model isoterm adsorpsi Asam Humat Kotoran Kuda terhadap logam Ni (II). Adsorpsi logam Ni (II) pada AHKK mengikuti model isoterm adsorpsi Langmuir. Hasil penelitian menunjukkan bahwa Asam Humat dapat diekstraksi dari kotoran kuda, dan dapat mengadsorpsi logam Ni (II) pada situs aktifnya. Adsorpsi yang terjadi hanya pada lapisan tunggal, yang berarti situs aktif pada permukaan adsorben memiliki kemampuan adsorpsi yang sama dan terdistribusi secara merata.

Pomelo fruit peel, an organic waste, was utilised as a biosorbent to remove Ni(II) from aqueous solutions. Some major factors influencing Ni(II) uptake such as pH, adsorption time, and initial Ni(II) concentration were examined. Several isotherm and kinetic models including the Langmuir, Freundlich, Sips, pseudo-first-order, pseudo-secondorder, and intra-diffusion models were fit to the experimental data. Results showed that the Ni(II) uptake obtained an equilibrium at pH=6 after 80 min at 303 K. The Sips isotherm model described the Ni(II) adsorption better than other models and the monoadsorption capacity calculated from the Langmuir model was 9.67 mg/g. The adsorption of Ni(II) followed pseudo-second-order kinetic models with three stages.

Mine water from upwellings in Commerce, Oklahoma is treated by the Mayer Ranch Passive Treatment System (MRPTS) to remove contaminants. Nickel [Ni(II)] and zinc [Zn(II)], which are toxic to both plants and animals when present in elevated concentrations, are still detectable at the effluent of the system out of the polishing pond (also known as Cell 6). Research has shown that living algae are capable of both adsorption and absorption of metals, whereas dead algae biomass can only adsorb metals due to the absence of metabolic processes. Previous exposure to metal contaminants influences the metal uptake efficiency of algae, as well as future growth rates when contaminants are present. Researchers have hypothesized that sorbed metals will be released from algae detritus as the algae decomposes. This research examined Ni(II) and Zn(II) sorption and release by a community of mixed algae species collected from MRPTS. Effluent water from MRPTS containing detectable levels of both Ni(II) (>0.015 mg/L) and Zn(II) (>0.25 mg/L) was used to create elevated concentration solutions (0.5, 2.0, 5.0, 10.0, and 20.0 mg/L) of both Ni(II) and Zn(II). A solution of MRPTS final cell effluent water with no addition of Ni(II) or Zn(II) also was included, along with a no-algae control solution with Ni(II) and Zn(II), for comparison of results. All analyses were performed in triplicate. Samples were incubated in the laboratory to mimic changing seasonal environmental conditions to which the native algae community in a passive treatment system (PTS) would be exposed, thus causing growth, death, and decomposition of that algae. Algae and associated solutions for each sample at the end of each phase (growth, chilled, and decomposition) were processed using microwave-assisted acid digestion to extract the metals present in the samples. The data obtained from these experiments showed sorption of both Ni(II) and Zn(II) by the algae community during the growth phase. The algae released a portion of the previously sorbed metals during the chilled phase. Samples showed continued sorption during the decomposition phase. Greater-concentration solutions had greater levels of sorption by the algae. The data followed the Langmuir isotherm model (R2>0.90), indicating that the principal metal removal mechanism was adsorption. These data indicate that algae, and ensuing decomposing algal biomass, both are capable of removing and retaining Ni(II) and Zn(II) from contaminated waters. Hence, natural algae populations within PTS can provide additional water treatment. [ABSTRACT FROM AUTHOR]

The research about the preconcentration of Ni(II) ions using Ca-alginate resin modified with dimethylglyoxime (DMG) as a material filler of the column has been done. The stage of preconcentration done by using the water sample was passed through the column, then eluted using HNO3. The amount of Ni(II) in the eluate was measured using atomic absorption spectrophotometer (AAS). Several important parameters in the preconcentration stage have been studied. The optimal condition at the stage of preconcentration Ni(II) ions was retention at pH 4, the volume of sample was 10 mL, the volume of HNO3 eluent was 4 mL at a concentration of 1.5 M, with the retention of capacity value was 2.4657 mg Ni(II)/g resin. The analytical performance of this method is good, showed with repeatability value as a percentage of the coefficient of variance value was 4.06%, and can increase the limit detection of Ni(II) ions was 3.94 times if compared to direct measurements with AAS. The method can be applied to the determination of Ni(II) ions in the water samples from Mahakam river at port Samarinda with recovery percentage value was > 95 %, indicating that the matrix of samples did not affect the results of measurements.

The thioester compound of 2-benzoylthiobenzimidazole was prepared by S-acylation of 2-mercaptobenzimidazole with benzoyl chloride and reactions of divalent Ni, Pd, and Pt salts with one equivalent of thioester compound a new complexes were isolated in a high percentage. A tetradentate thioester compound and a bivalent metal complexes were identified by CHNS analysis, IR, magnetic susceptibility, molar conductivity, UV-Vis, and 1H, 13C NMR spectroscopies. The anti-bacterial activity of the thioester compound and the bivalent metal complexes were studied using disk diffusion test method against the bacterial species, Staphylococcus aureus, and Pseudomonas aeruginosa. The divalent metal complexes demonstrated a greater activities compared to thioester compound a lone. Structural analysis showed that 2-benzoylthiobenzimidazole L behaves as a neutral four coordination modes compound and bonds to the bivalent metals cation through two nitrogen, sulfur and oxygen atoms. Our study informed the formation of four-coordinate square planar complexes structure around divalent metal salts of Ni, Pd, and Pt.

Maintaining a high quality of water resources is always the top priority as water is highly essential in many aspects. However, contamination of water resources, especially due to the improper discharge of industrial wastewater is drawing attention. Poorly or untreated industrial wastewater is usually severely polluted with hazardous materials such as heavy metals. Therefore, this study intended to prepare a facile-fabricated porous geopolymer sphere and investigate its potential as an adsorbent for the removal of Ni(II) from wastewater. Porous geopolymer spheres can be beneficial for direct use in packed bed systems and can be retrieved easily upon being exhausted. Results demonstrated that at the equilibrium contact time of 48 h, the Ni(II) uptake capacity of porous geopolymer spheres was approximately 3.4 times greater than non-foamed geopolymer spheres. The large pore size and open porosity network that exist in porous geopolymer spheres enhance the adsorption performance as these factors allow easy penetration of Ni(II). The optimum pH was found to be pH 5. The pH can greatly affect the removal performance, where low pH results in competition for binding sites between H+ and Ni(II), while high pH induces the precipitation of Ni(OH) 2. The maximum Ni(II) removal capacity obtained from the isotherm study was 19.94 mg/g. [ABSTRACT FROM AUTHOR]