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Arsenic containing non-ferrous metal and precious metal sulfide ore will produce acidic high concentration arsenic solution in the smelting process, which has the characteristics of high arsenic concentration, complex composition, large changes, strong toxicity and difficult to store, such as direct discharge without treatment, will have a great impact on the environment and human health. In this paper, the principles, advantages and disadvantages of chemical precipitation method, evaporation enrichment method and metal powder method are reviewed, as well as the research progress of each method, so as to provide reference for the development of arsenic removal technology. [ABSTRACT FROM AUTHOR]

This study uses a novel sintering technique at very low temperatures (below 300°C) named the Cold Sintering Process to produce highly dense Hydroxyapatite (HA) samples. Nano hydroxyapatite was prepared using two different methods: Synthesis by chemical precipitation method (HA1) and natural source from Boven bone (HA2). The samples are characterized using scanning electron microscope (SEM), X-ray energy dispersive spectrometry (EDS), X-ray diffractogram (XRD), transition electron microscope (TEM), Fourier transform infrared spectrometry (FTIR) and Nuclear magnetic resonance spectroscopy (NMR). Also, physical and mechanical properties measurements were detected, including density and hardness. The results indicated that cold sintering could result in Hydroxyapatite with high densification, high purity, and high stability without thermal decomposition compared with traditional sintering. The relative density and hardness for HA1 are 99% and 502HV, respectively. The relative density and hardness for HA2 are 69% and 350HV, respectively. It can be observed that the HA1 sample has higher densification than HA2 due to the presence of organic matter in natural Hydroxyapatite HA2. This organic material will be removed during the cold sintering process, leaving pores that lead to low densification of HA2 samples. It can be concluded that the synthesis hydroxyapatite (HA1) can be easily sintered by a cold sintering process compared with natural one(HA2).

In industrial production, a large amount of ferrous sulfate waste liquid is produced every year, and the output of iron and steel deep processing process is the largest. Ferrous sulfate waste liquid contains sulfuric acid with low pH value and metal ions such as Hon, cobalt, nickel, aluminum and chromium. Direct discharge not only wastes metal resources, but also causes serious pollution to soil and water. How to comprehensively recover ferrous sulfate waste liquid has great economic benefits for enterprises and certain environmental benefits for society. At present, the main treatment methods are neutralization treatment, chemical precipitation, crystallization precipitation, solvent extraction, microbial method and so on. According to the ferrous sulfate waste liquid produced in different production processes, corresponding treatment methods should be adopted. Because a large amount of metal sludge will be produced by neutralization method, the product market demand of crystallization precipitation method is low, the treatment capacity of solvent extraction method is low, and the treatment cycle of microbial method is long, so chemical precipitation method is the main recovery method at present The chemical precipitation method is easy to operate and does not need high-performance equipment, but there are many influencing factors in the test and the product properties fluctuate greatly. From ferrous sulfate waste liquid recovered products are mainly used in pigment industry, water treatment industry, magnetic materials industry and so on. Most products only use iron in waste liquid, but sulfuric acid and sulfur are not recovered. HOW to comprehensively recover waste liquid is a research focus. Because there are many impurity elements in ferrous sulfate waste liquid, it is very difficult to purify it, and the production cost is also high. Therefore, how to directly utilize the waste liquid is also the main research direction in the future. [ABSTRACT FROM AUTHOR]

Cu-removal operation is one of the vital purifying processes for the nickel electrolysis anolyte. Different from the nickel concentrate-activated anode slime-sulfurous acid, NiS and MnS, hydrogen sulfide (H2S) introduced less metal impurities into the systems. And the precipitation theory is the main principles of nickel purification method utilizing H2S in removing Cu from the anolyte rather than these replacement reactions. The Solubility Product Constant (Ksp) of CuS is lower than NiS, which indicates that the precipitate of CuS can be highly efficiently and selectively formed and easily removed from the nickel anolyte. In this research, the effects of mole ratio of [H2S]/[Cu], pH, temperature, potential–pH diagrams and the precipitates of metal sulfides were investigated. The experimental results show that the H2S was a potential successor as the highly efficient and selective Cu-removal reagent. The concentration of Cu2+ in Watts can be reduced to lower than 0.002 g/L, and the mass ratios of Cu/Ni in this precipitate are larger than 15 in the low pH state (1.0–1.5). S, CuS, Cu2S, NiS, NiS2 or Ni3S2 may be presented and coexisted in the region that concluded from the analysis of potential–pH diagram. The XRD analysis of precipitates indicated that it was composed by CuS and NiSO4·6H2O. The XPS measurement shows that the valence states of Cu and Ni are Cu2+ and Cu+ and Ni2+, respectively. The valence state of S includes the S2−, Sx2− and SO42− states. Therefore, H2S can highly efficient and selective remove the Cu2+ from the low pH nickel Watts solution, and which can be applied on the nickel anolyte purification in the future. [ABSTRACT FROM AUTHOR]

Chemical precipitation method was used to prepare of Zn0.96Ni0.04S nanoparticles. XRD showed that ZnS:Ni2+ nanoparticles crystallized in zinc blend structure with preferential orientation by the side of (111) plane. Scanning electron microscope (SEM) images of Zn0.96Ni0.04S nanoparticles portray substantial agglomeration of particles with potholed spherical morphology and energy dispersive spectrum (EDAX) measurements incorrigible that the presence of Ni in ZnS lattice. High resolution tunneling electron microscope (HRTEM) divulge that Zn0.96Ni0.04S particle size were ranges from ∼ 15 to 20 nm with good crystalline character and SAED pattern were good concurrence with X-ray diffractive (XRD) results. UV–Vis spectroscopy was engage to evaluate optical band gap of Zn0.96Ni0.04S nanoparticle, and which further disclose that when 3-mercaptopropionic (MPA) concentration increase guide the absorption edge shifted to lower wavelength. Peak at 411 °C with matching weight loss of 39.2 wt% in DTA reveals that Ni2+ ions are get away from the ZnS matrix. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She 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.)

Zinc Oxide (ZnO) nanoparticles (NPs) have been synthesized by a simple chemical precipitation method. The effect of monoethanolamine (MEA) content in different solvents on ZnO NPs synthesis and their structural properties has been investigated. The NPs synthesized by using isopropanol (IPA) with 15 ml MEA as a stabilizer under the most favorable conditions (deposition time, td = 120 min, temperature = 60 °C) showed good structural properties. Synthesized NPs exhibited beneficial structural properties after annealing. The hexagonal wurtzite crystal structure of ZnO NPs was verified by XRD. Different models were used to calculate structural parameters such as crystallite size, strain, stress, and energy density for all the reflection peaks of XRD corresponding to ZnO lying in the range 2θ = 15⁰–80⁰. The crystallite size of the ZnO nanoparticles was found to be 50–60 nm. FTIR and EDX confirmed the presence of ZnO NPs in the samples. SEM micrograph of all the samples revealed that the grain sizes decrease gradually with the increase of the amount of MEA. UV–Visible diffuse reflectance spectroscopy results provide evidence that the ZnO NPs possess broader absorption bands, together with high band gap energy. The ZnO NPs synthesized with IPA solvent have the highest transmittance and band gap energy of 3.3eV. According to DLS data, various content of MEA stabilizer in solvent affects the hydrodynamic size of ZnO NPs.

Advancing inverted (p‐i‐n) perovskite solar cells (PSCs) is critical for commercial applications given their compatibility with different bottom cells for tandem photovoltaics, low‐temperature processability (≤100 °C), and promising operational stability. Although inverted PSCs have achieved an efficiency of over 25 % using doped or expensive organic hole transport materials (HTMs), their synthesis cost and stability still cannot meet the requirements for their commercialization. Recently, dopant‐free and low‐cost non‐stoichiometric nickel oxide nanocrystals (NiOx NCs) have been extensively studied as a low‐cost and effective HTM in perovskite optoelectronics. In this minireview, we summarize the synthesis and surface‐functionalization methods of NiOx NCs. Then, the applications of NiOx NCs in other perovskite optoelectronics beyond photovoltaics are discussed. Finally, we provide a perspective for the future development of NiOx NCs for the commercialization of perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

In order to obtain up-conversion luminescent materials with bright red emission, a series of Yb3+, Er3+, Mn2+- doped Gd2O3 microcrystals were prepared by simple chemical precipitation method, and their morphology, structure and luminescent properties were characterized. The results show that Gd2O3 :10%Yb3+, 1% Er3+ microcrystals exhibit a flower-like morphology, and the average diameter is 2. 28 μm. After calcination at high temperature, the sample presents a cubic Gd2O3 structure with good crystallinity, and Mn2+ doping does not affect the morphology and crystal phase of the product. Under 980 nm near-infrared light excitation, Gd2O3 : 10% Yb3+, 1% Er3+ microcrystals show orange-red luminescence, which corresponds to the 4F9/2→4I15/2 transition of Er3+. With the increase of Mn2+ doping concentration (molar fraction), the luminescence intensity of Gd2O3:10% Yb3+, 1% Er3+, x% Mn2+ microcrystals first increases and then decreases, and the luminescence color gradually turns to red, which is consistent with the CIE color coordinate. At the same time, the up-conversion luminescence mechanism and the possible energy transfer process of Gd2O3: 10% Yb3+, 1% Er3+, x% Mn2+ microcrystals were analyzed according to the relationship between luminescence intensity and excitation power. [ABSTRACT FROM AUTHOR]

Copyright of Hydrometallurgy of China is the property of Hydrometallurgy of China 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.)

Photocatalysis is the most environmentally benign and efficient method for degrading organic dyes in water purification. Herein, the synthesis of ZnO nanoparticles was achieved by simple homogeneous chemical precipitation via the support of adipic acid and followed the calcination process at elevated temperatures. Based on the physical and morphological characterization analysis, the high crystallinity hexagonal structure with uniform granular shape morphology of the ZnO nanoparticles was formed with a band gap of 3.2 eV. The photocatalytic performance of the ZnO nanoparticles was investigated with the degradation of methylene blue (M.B.) dye as a model compound in an aqueous medium under UV light irradiation. The optimal ZnO‐700 nanoparticles demonstrated the highest photocatalytic activity thanks to their large surface area and numerous oxygen vacancies. More importantly, a small amount of photocatalyst (0.4 g/L) successfully degraded M.B. dye from an aqueous solution with 100 % efficiency within just 11 minutes of irradiation time under UV light with protective photocatalytic activity 4 sequential cycles. Besides, in‐depth photocatalysis experiments present that via a facile two‐step synthesis method, the as‐prepared ZnO photocatalysts depict enhanced chemical stability in a harsh environment and efficient photodegradation. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group 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.)

In the current study, the combined anti-tumor efficacy of bioactive hydroxyapatite nano- particles (HA-NPs) loaded with altretamine (ALT) was evaluated. The well-known fact that HA has great biological compatibility was confirmed through the findings of the hemolytic experiments and a maximum IC50 value seen in the MTT testing. The preparation of HA-NPs was performed using the chemical precipitation process. An in vitro release investigation was conducted, and the results demonstrated the sustained drug release of the altretamine-loaded hydroxyapatite nanoparticles (ALT-HA-NPs). Studies using the JURKAT E6.1 cell lines MTT assay, and cell uptake, as well as in vivo pharmacokinetic tests using Wistar rats demonstrated that the ALT-HA-NPs were easily absorbed by the cells. A putative synergism between the action of the Ca2+ ions and the anticancer drug obtained from the carrier was indicated by the fact that the ALT-HA-NPs displayed cytotoxicity comparable to the free ALT at 1/10th of the ALT concentration. It has been suggested that a rise in intracellular Ca2+ ions causes cells to undergo apoptosis. Ehrlich's ascites model in Balb/c mice showed comparable synergistic efficacy in a tumor regression trial. While the ALT-HA-NPs were able to shrink the tumor size by six times, the free ALT was only able to reduce the tumor volume by half. [ABSTRACT FROM AUTHOR]

In the present work, pure and Sn-doped CeO2 nanoparticles (NPs) were synthesized by the chemical precipitation method calcined at 400 °C for 4 h. Characterization of NPs was done through X-ray diffraction (XRD), UV-visible, photoluminescence (PL), Fourier transform infrared (FTIR) spectroscopy and high-resolution electron microscope (HRTEM) techniques. The XRD study revealed the crystalline nature, size, and structure of the prepared NPs. The HRTEM results illustrated cubic structure. The UV-visible and PL studies were used to measure the optical behaviors of CeO2 NPs. The UV-visible showed that the bandgap value of CeO2 NPs increased from 3.61 to 3.65 eV for different doping concentrations. The XRD study exhibited that the size of the CeO2 NPs reduced from 11.03 to 7.91 nm. From the TEM analysis, the average size of undoped and 10% Sn-doped CeO2 NPs was calculated as 9.3 and 7 nm, respectively. A cyclic voltammetric study confirmed that Sn-doped CeO2 exhibited a higher specific capacitance value than the pure CeO2. The chemical precipitation method observed excellent redox and oxidation behavior were observed for Sn-CeO2 NPs by the cyclic voltammetric study. The significant enhancement in the specific capacitance suggested that Sn-doped CeO2 is a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Herein we describe an effective route for the degradation of methyl green (MG) dye under visible light illumination by pristine and strontium (Sr)-doped zinc oxide (ZnO) photocatalysts (synthesized by the simple chemical precipitation method). The x-ray diffraction structural analysis has confirmed that both photocatalysts exhibit the hexagonal wurtzite structure; without any additional phase formation in Sr-doped ZnO, in particular. The optical properties of the synthesized photocatalysts have been investigated using UVâ€"vis absorption spectroscopy in the wavelength range of 250â€"800 nm. Through Tauc’s plot, the slight decrease from 3.3 to 3.2 eV in band gap energy has been elucidated (in the case of Sr-doped ZnO), which has been further confirmed by the quenching in the intensity of Photoluminescence (PL) emission spectrum. This may be due to sub-band level formation between valence and conduction band, caused by the impregnation of Sr2+ ions into ZnO host. The morphological study has also been performed using Field Emission Scanning Electron Microscope, which indicates nanoparticles (NPs) based surface texture for both photocatalysts. During the photocatalytic activity study, after 30 min irradiation of visible light, ∼65.7% and ∼84.8% photocatalytic degradation of MG dye has been achieved for pristine and Sr-doped (2 wt%) ZnO photocatalysts, respectively. The rate of photocatalytic reaction (K) has been observed to be ∼0.06399 minâˆ'1 for Sr-doped (2 wt%), whereas nearly half magnitude ∼0.03403 minâˆ'1 has been observed for pristine ZnO, respectively. The significantly improved photodegradation activity may be ascribed to the relatively broader optical absorption capability, surface defects and the enhanced charge separation efficiency of the Sr-doped ZnO photocatalyst. [ABSTRACT FROM AUTHOR]

The band-gaps of wide band gap metal sulfide semiconductors such as ZnS, are significantly reduced when doped with transition metal ions Ni2+. The new composite materials offer promising and versatile applications in spintronic devices, solar cells and other optoelectronic devices, and in photonics etc. It has led to substantial modifications in methods of synthesis for ZnS nanoparticles. In this research work, we have synthesized ZnS nanoparticles via simple chemical precipitation method. ZnS nanoparticles have been characterized using UV-visible spectra and Raman spectroscopy. For morphological studies we have used scanning electron microscopy (SEM). The optical band gap has been evaluated from UV-vis-nir absorption spectrum of the particles. Raman spectroscopy is used to study the rotational, vibrational and other modes of the sample, as we are interested to reveal properties of nanoclusters treating as those as nano-molecules. We correlate the variations in properties with their structures. Our investigations confirm formation of large single crystals (nanomolecules) yielding resonant Raman peaks. It is further confirmed from SEM images of the samples. Nanoparticles have special properties other than bulk. Their surface energy contributions are entirely different from their bulk counterparts and play dominant role in its stability. Thus, we assign a special phase for them as "Nanophase". The phenomenon of nano-cluster (aggregates) formation of nickel atoms via nucleation is also confirmed for high doping concentrations of nickel, which results into inverse trend for band-gap. [ABSTRACT FROM AUTHOR]

In this paper, α-Fe2O3 was prepared by hydrothermal and chemical precipitation methods, respectively, and its gas sensing properties toward CH4 were systematically studied. The larger specific surface area of the materials provided them potential and considerable gas adsorption abilities. The results of gas-sensing measurements indicated the synthesized α-Fe2O3 materials presented a p-type conductive nature. The sensitivities of the devices based on the different material fabrication methods were measured to be 195% and 214%, respectively, at 370°C for the concentration of 2000 ppm CH4. In addition, the sensing mechanism was discussed and simulated by first-principles calculation. The results revealed the higher surface adsorption energy of α-Fe2O3, which verified the experimental conclusions of our work. Our research suggests that α-Fe2O3 is a promising candidate for CH4 gas sensing in many fields such as mining safety and environmental monitoring. [ABSTRACT FROM AUTHOR]

Nowadays, antimicrobial agents are currently being employed using noble metal nanoparticles such as gold and silver. NiO nanoparticles are a good alternative in this case, since they are less expensive than gold and silver. Antimicrobial agents are very important in textiles, water disinfection, medicine and food packaging. Most of these applications employ nanoparticles of specific shape, size and chemical composition. For these reason, present work focuses on synthesis of Nickel oxide nanoparticles by Chemical precipitation method. Obtained particles by this method were characterizes for their structural, optical, and antimicrobial properties after calcination process at various temperature of 400 °C, 600 °C, and 800 °C at 2 h. The Rietveld refinement was carried out to obtain the crystal structure and purity of synthesis was achieved. The analysis of peak broadening was performed to estimate the discrepancy in crystallite size and microstrain components of the nanoparticles with the calcination temperatures and were compared with Transmission Electron Microscope results. The calculated band gap value varies from 3.37 to 3.3 eV by increasing the calcination temperature. The emission peak at 490 and 580 nm affirmed the presence of defects in the NiO lattice. The formation of NiO was confirmed using FTIR for all the calcination at different temperatures nanoparticles. Antimicrobial activities of prepared nanoparticles were tested against selected four distinct pathogenic bacterial and three non-identical fungi species by the disc diffusion method. Results of the zone of inhibition values (mm) indicate that the test samples were exhibited significant antimicrobial activity. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group 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.)

Development photoinduced photocatalysts is a significant approach to improve photocatalytic activity and stability. Herein, we successfully prepared Zn x Cd 1 − x S / CeO 2 composites by a facile method. It is found that the Zn x Cd 1 − x S / CeO 2 composites show significant enhancement in photocatalytic activity for methyl orange (MO) degradation under visible and UV light irradiation. The degradation efficiency reaches up to 3.7 times higher than that of pure CeO 2 under visible light irradiation. Moreover, the Zn x Cd 1 − x S / CeO 2 samples have almost no loss of photocatalytic activity after five recycles, indicating good photocatalytic stability of the samples. The attractive photocatalytic activity of the Zn x Cd 1 − x S / CeO 2 samples could b e attributed to the robust charge carriers transfer and separation. [ABSTRACT FROM AUTHOR]

In this study, the impinging stream-rotating packed bed and precipitation method were used to continuously prepare Fe and Co co-doped Titanium Dioxide by in-situ modification. With TiOSO4 solution containing Fe and Co2+ and NH3·H2O were sprayed on the packing and sheared by the packing that rotated at a high speed, resulting in improvement of microscopic mixing. The prepared catalyst is anatase with a particle size of 14 nm and a specific surface area of 194.34 m2/g. The photoresponse range is extended to 550 nm with a band gap of 2.5 eV. The photoluminescence results show that doping of Fe and Co can effectively inhibit the recombination of photogenerated electron-hole pairs. The percentage decomposition of 100 mg/L phenol under UV and visible light irradiation for 2.5 h is 88.71% and 24.58%, which is 1.59 and 2.07 times that for pure TiO2. [ABSTRACT FROM AUTHOR]

In this study, copper hydroxide sulfate (Cu4(OH)6SO4) was synthesized by chemical precipitation using CuSO4 as the precursor material and the first time borax as basic precipitating agent. The synthesized samples were characterized using XRD, FTIR, and SEM. The decomposition kinetics of Cu4(OH)6SO4 were examined by the thermoanalytical procedures. It was obtained from TG‐DTG data that Cu4(OH)6SO4 has two‐region decomposition at elevated temperatures. Kinetic parameters of these regions were calculated by using both the model‐fitting and model‐free methods. In the decomposition of copper hydroxy sulfate, the mean activation energy for first region was calculated as 90.88 kJ mol−1 from KAS method and 91.47 kJ mol−1 from FWO method. The mean activation energy for the second region was 207.20 kJ mol−1 from KAS and 213.34 kJ mol−1 from FWO. The activation energies for first and second regions were obtained from Ortega method as 56.3 and 198.3 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

The aim of the present work is to investigate the change in thermal conductivity and stability of copper oxide (CuO) water-based nanofluids, which are prepared by a two-step process, with different concentrations of anionic (Sodium dodecyl sulfate SDS) and nonionic dispersants (Polyvinyl pyrrolidone PVP). Further, CuO nanofluids and nanoparticles have been characterized by XRD, EDX, FESEM, TEM, DLS, and UV to examine the particle size, elemental composition, morphology, particle size distribution, and band gap. Besides, thermal conductivity and stability of all the fluid samples have been measured with respect to particle volume fraction. The interpretation of particle stability in different weight percent of dispersants in base fluids in the presence of PVP dispersant results in a better stabilizing agent than SDS at higher particle volume fraction. Finally, evaluating the effect of lower dispersant concentration (0.1–0.5 wt%) and particle size on the thermal conductivity of CuO water-based nanofluids confirmed that the significant enhancement of thermal conductivity is observed at lower dispersant concentration and decreases with increase in particle size. The enhancement of thermal conductivity was found to be 38% and 34% at 0.4 wt% of SDS and PVP dispersants. [ABSTRACT FROM AUTHOR]

ZnO–ZnSe heterostructures were successfully synthesized by single step chemical precipitation method at room temperature. The obtained composite structures were systematically characterized for structural, morphological, optical, and vibrational properties using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), High-resolution transmission electron microscopy (HRTEM), UV–Vis DRS, photoluminescence spectroscopy (PL), and Fourier-transform Raman spectroscopy (FT-Raman). XRD patterns of the synthesized samples exhibit peaks corresponding to wurtzite ZnO and ZnSe structures which primarily confirmed the formation of single phase heterostructures. ZnO microspheres grown over the surface of ZnSe nano cauliflower clusters obtained from the FESEM images confirmed the formation of ZnO–ZnSe heterostructures. A sharp peak around 290 nm in UV–Vis DRS absorption spectra corresponds to ZnSeO3 and a wide weak absorbance is observed in the visible region (ranging from 370 to 663 nm) corresponding to the nanocomposite structure. In the Raman spectra, the surface phonon mode which is the characteristic feature of the ZnO–ZnSe heterostructures is observed at 237 cm−1. Based on the characterization results, the photocatalytic properties of ZnO–ZnSe nanoparticles were evaluated for the degradation of methylene blue (MB) and was found to exhibit solar photocatalytic property. [ABSTRACT FROM AUTHOR]

Bone supports animal bodies, is the place where blood is produced, and is essential for the immune system, among other important functions. The dominant inorganic component in bone is hydroxyapatite (Hap), the structure and dynamics of which still pose many unsolved puzzles. An updated understanding of HAp is of great significance to osteology, dentistry, and the development of artificial bone and other biomaterials. In this work, HAp nanoparticles were synthesized with the wet chemical precipitation method and their structure and morphologies were controlled by varying pH and adding fluoride ions by two different routes: (1) fluoride ions were added during synthesis, and (2) fluoride ions were introduced after the samples were synthesized by soaking the samples in solutions with fluoride ions. XRD and HRTEM were employed to confirm the composition and structure, while various multinuclear (1H, 19F, 31P) solid-state nuclear magnetic resonance (NMR) methods including 1D single pulse, cross-polarization under magic-angle spinning (CPMAS), and 2D heteronuclear correlation (HETCOR) were used to characterize the structure, morphology, and dynamics, validating the general core-shell morphology in these F-HAp samples. It was found that all hydroxide ions were substituted when the fluoride ion concentration was above 0.005 M. An NMR peak corresponding to water structure emerged and the bulk water peak was shifted upfield, indicating that fluoride substitution modifies both the crystalline core and the amorphous shell of F-HAp nanoparticles. With the second route of fluoride substitution, increases in soaking time or fluoride ion concentration could increase fluoride substitution in HAp, but could not achieve complete substitution. Finally, with 1H-31P CPMAS and HETCOR, it was established that there are two types of phosphorous, one in the crystalline core (PO43−) and the other in the amorphous shell (HPO42−). These results are valuable for clarifying the fluoride substitution mechanism in HAp in biomaterials or in organisms, and provide insights for developing next generation replacement materials for bone, tooth, or coating films, drug delivery systems, etc.

A unique method of preparing TiO2/sericite composite particles material was investigated by coating anatase TiO2 on the surface of sericite via chemical precipitation method. The results of X-ray diffraction, scanning electron microscope, infrared spectra and X-ray photoelectron spectroscopy indicated that TiO2 coated uniformly on the surface of sericite, and Si-O-Ti chemical bonds are formed during the thermal treatment process. The hiding power of Ti/SE-CPM composite is up to 85% of TiO2 white pigments, and the oil absorption value was equal to TiO2 white pigments. All these data demonstrated that the obtained Ti/SE-CPM samples have similar excellent properties compared with anatase TiO2 white pigments. Therefore, this study provides a feasible way of reducing the usage of TiO2 while maintaining similar pigment properties, which, of course, will reduce the cost, protect our environment and has a potential application in large-scale production of white pigments. [ABSTRACT FROM AUTHOR]

CeO 2 -SnO 2 nanocomposites were synthesized by simple chemical precipitation method. The composites were characterized by XRD, UV–vis, SEM, FE-SEM, HR-TEM, FT-IR and FT-Raman. X-ray diffraction result confirms the structure with good crystalline and size of the nanocomposites. HR-TEM results revealed formation of nanocomposite in spherical shape with less than 10 nm size and highly homogeneous. X-ray photoelectron spectroscopy confirmed the chemical composition and different ionization states of Ce3+/Ce4+, Sn4+ and O1s. Functional groups of nanocomposites were identified using FT-IR spectroscopy. FT-RAMAN spectra were used to identify the Raman shift, which supported the formation of nanocomposite. Thermal stability and phase changes of CeO 2 -SnO 2 nanocomposite were characterized by TG and DTA. Paramagnetic property of the nanocomposite at room temperature was studied by EPR technique. The results of cyclic voltammetry and amperometry studies demonstrated the electrocatalytic activity of CeO 2 -SnO 2 nanocomposites towards l -cysteine oxidation. The electrochemical studies showed that CeO 2 -SnO 2 composite detects L-cysteine linearly over a concentration range from 0.016 × 10−3 M to 2 × 10−3 M. The electrochemical sensor showed high sensitivity of 186.34 μA mM−1 cm−2 with lower detection limit of 0.016 × 10−3 M. Moreover, the sensor results showed good selectivity, excellent stability and reproducibility of the CeO 2 -SnO 2 nanocomposites as a promising candidate for L-cysteine sensing. Image 1 • CeO 2 -SnO 2 nanocomposites were synthesized by a simple chemical precipitation method. • The nanocomposite size was 10 nm with highly homogeneous. • The CeO 2 -SnO 2 was used as modify electrode for determination of the L-cysteine biomolecules. • Sensor results showed good selectivity, excellent stability and reproducibility. [ABSTRACT FROM AUTHOR]

In this study, benzimidazole and Zn2+ are deposited on the surface of AP particles through chemical precipitation to improve its thermal properties, energy properties and hygroscopicity. The results show that compared with pure AP, the HTD peak temperature and apparent activation energy of the AP@ZIF-7 (25 wt%) sample are reduced by 98.49 °C and 117.62 kJ·mol−1, respectively. The heat release during thermal decomposition increases by 1133.62 J·g−1. In addition, the contact angle between AP@ZIF-7 (25 wt%) and water is 79.19°, which is 66.09° higher than that of AP. At the same time, after being placed at a relative humidity of 88% for 72 h, its moisture absorption rate drops to 0.05 wt%, a decrease of 0.266 wt%. Moreover, compared with the propellant prepared with AP as oxidant, the burning rate of the propellant containing AP@ZIF-7 (25 wt%) increases by 5.28 mm·s-1, and the flame temperature increases by 873.17 °C. ZIF-7 was deposited on the surface of AP particles by chemical precipitation method, which is expected to comprehensively improve the hygroscopic, energy and thermal properties of AP. [Display omitted] • The ZIF-7 layer can cover the surface of AP particles uniformly and compactly. • The AP@ZIF-7 composites were successfully prepared. • The ZIF-7 layer can improve the thermal decomposition of AP. • The layer of ZIF-7 can improve the anti-hygroscopic performance of AP. • AP@ZIF-7 can increase the burning rate and burning temperature of the propellant. [ABSTRACT FROM AUTHOR]

Europium-doped hydroxyapatite Ca10(PO4)6(OH)2 (3% mol) powders were synthesized by an optimized chemical precipitation method at 25 °C, followed by drying at 120 °C and calcination at 450 °C and 900 °C. The obtained nanosized crystallite samples were investigated by means of a combination of inductively coupled plasma (ICP) spectroscopy, powder X-ray diffraction (PXRD), Fourier Transform Infrared (FTIR), Raman and photoluminescence (PL) spectroscopies. The Rietveld refinement in the hexagonal P63/m space group showed europium ordered at the Ca2 site at high temperature (900 °C), and at the Ca1 site for lower temperatures (120 °C and 450 °C). FTIR and Raman spectra showed slight band shifts and minor modifications of the (PO4) bands with increasing annealing temperature. PL spectra and decay curves revealed significant luminescence emission for the phase obtained at 900 °C and highlighted the migration of Eu from the Ca1 to Ca2 site as a result of increasing calcinating temperature.

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Abstract Copper oxide (CuO) nanomaterials (NMs) of different size and morphology were synthesized by Chemical precipitation, Microwave irradiation and Hydrothermal method and characterized by TEM, BET, FTIR, XRD and EDX analysis. As synthesized CuO NMs were utilized for elimination of harmful dyes viz. Direct Red 81 (DR-81) and Coomassie Brilliant blue R-250 (BBR-250) and pathogenic bacteria (Staphylococcus aureus). Owing to their morphology, smaller size and relatively high surface area (40.320 m2 g−1), CuO NMs prepared by chemical precipitation method were observed to show better adsorption capacity for both the dyes (68.70 (DR-81) and 73.04 (BBR-250) mg g−1). The influence of different experimental conditions was studied by the methodical assessments of various parameters such as pH, adsorbent dose, concentration and contact time. Moreover, different adsorption isotherms and pseudo-second order kinetic model were applied to understand the adsorption mechanism. Langmuir model was found to be best fit thus confirming the monolayer adsorption process. To ensure the practical utility of CuO NMs for organic waste removal, the adsorption studies were performed in the presence of different inorganic ions and real water samples. In addition, recovery of the dye and NMs were also carried out effectively by simple method, thus avoiding the secondary pollution. CuO NMs were observed to exhibit significant antibacterial activity against the human pathogenic bacteria. These studies demonstrated that synthesized CuO NMs showed good adsorption efficiency for the removal of harmful dyes and antimicrobial activity against the pathogenic bacteria, which vary as a function of size and surface area. Highlights • Facile and non-toxic methods to synthesize CuO NMs of various shape and size. • CuO NMs exhibited effective dye removal and significant antibacterial activity. • CuO NMs were also efficient in eliminating dyes from field samples. • NMs fabricated via chemical precipitation method demonstrated better results. • NMs were successfully recovered with excellent chemical stability and further reused. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization and the rapid development of industry and agriculture, a large number of industrial wastewater containing heavy metal is produced. Heavy metal ions are not easily degraded and are highly harmful. Removal of heavy metal ions in industrial wastewater is the main way to reuse wastewater. The method for removing heavy metal ions from industrial wastewater based on chemical precipitation method is proposed in this paper, which utilizes instruments and reagents to fuse metal ion solution and industrial wastewater by preparing heavy metal ion solution, industrial wastewater and adsorbent. Calcium hydroxide is placed in the industrial wastewater solution to cause the direct chemical reaction with the heavy metal ions therein. Through a series of processes such as decomplexation reaction, sedimentation, and detection of heavy metal ion concentration, the precipitate that is hardly soluble in water is finally formed, and it is absorbed by the biofilm adsorbent. The experimental results show that pH value, reaction time, adsorbent dosage and initial concentration of metal ions have great influence on the proposed method. The removal ability of heavy metal ions can be improved by adjusting the influencing factors, which provides the theoretical basis for practical application of heavy metal industrial wastewater. [ABSTRACT FROM AUTHOR]

With the use of Paulownia wood as a substrate and a vacuum impregnation method, CaCO3/wood composites were prepared. The XRD results showed that a variety of types of calcium carbonates coexisted in the composite and the elevated temperature was favorable for the aragonite type. The SEM results showed the modified wood retained the original wood structure and that CaCO3 was uniformly distributed in the wood cell cavity and clung to the wood cells. The mechanical testing results showed that the mechanical properties of all the composites were obviously improved; the maximum value of strength of compression (SC) and modulus of elasticity (MOE) of the CaCO3/wood composites were 32.23 MPa and 0.92 GPa, respectively, values 44.2% and 53.3% higher than those of the original wood. The maximum value of proportional limit (PL) of the composites was 29.4 MPa (38.5% increase from original wood). A cone calorimeter was used to investigate the flame retardation properties of CaCO3 on the composites. The value of the heat release rate and total heat release of composites were lower than those of the original wood; the CaCO3 wood composites showed good flame retarding effects. [ABSTRACT FROM AUTHOR]

new material of Cu(OH)2 nanostructures was prepared using cupric nitrate and sodium hydroxide as raw materials by the chemical precipitation method. The Cu(OH)2 nanostructures were characterized by scanning electron microscope, transmission electron microscopy, infrared spectrometer, and X-ray diffractometer. The results showed that the Cu(OH)2 nanostructures exhibited excellent uniform and dispersion at 40°C. A series of factors was investigated to effect the photocatalytic efficiency of methyl orange (MO), such as the concentration of Cu(OH)2 nanostructures, the reaction time of the Cu(OH)2 nanostructures, the initial concentration of MO, and so on. As a result, the Cu(OH)2 nanostructures exhibited excellent photocatalytic efficiency with the concentration of 20 mg L-1 Cu(OH)2 nanostructures, the initial concentration of MO was 15 mg L-1 and the stirring time was 70 min. [ABSTRACT FROM AUTHOR]

UV and solar-based photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) as an organic contaminant in ceramics industry wastewater by ZnS and Fe-doped ZnS NPs was the focus of this research. Nanoparticles were prepared using a chemical precipitation process. The cubic, closed-packed structure of undoped ZnS and Fe-doped ZnS NPs was formed in spherical clusters, according to XRD and SEM investigations. According to optical studies, the optical band gaps of pure ZnS and Fe-doped ZnS nanoparticles are 3.35 and 2.51 eV, respectively, and Fe doping increased the number of carriers with high mobility, improved carrier separation and injection efficiency, and increased photocatalytic activity under UV or visible light. Doping of Fe increased the separation of photogenerated electrons and holes and facilitated charge transfer, according to electrochemical impedance spectroscopy investigations. Photocatalytic degradation studies revealed that in the present pure ZnS and Fe-doped ZnS nanoparticles, 100% treatment of 120 mL of 15 mg/L phenolic compound was obtained after 55- and 45-min UV-irradiation, respectively, and complete treatment was attained after 45 and 35-min solar light irradiation, respectively. Because of the synergistic effects of effective surface area, more effective photo-generated electron and hole separation efficiency, and enhanced electron transfer, Fe-doped ZnS demonstrated high photocatalytic degradation performance. The study of Fe-doped ZnS's practical photocatalytic treatment capability for removing 120 mL of 10 mg/L 2,4-DCP solution made from genuine ceramic industrial wastewater revealed Fe-doped ZnS's excellent photocatalytic destruction of 2,4-DCP from real industrial wastewater. [Display omitted] • Use of Fe-doped ZnS NPs for photocatalytic degradation of organic pollutants. • UV and solar-based photocatalytic degradation methods for treatment of wastewater. • The degradation efficiency increased with Fe-doping in ZnS NPs. • Fe-doped ZnS NPs can be a promising material for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

• Inhibition of Ca2+ in municipal solid waste incineration fly ash is investigated. • Chemical precipitation and electrochemical methods are innovatively coupled. • Space-time migration laws of Ca2+ in an electrokinetic cycle are studied. • Carbonate inhibition mechanism are revealed. • Effect of voltage gradient on Ca2+ precipitation is greater than that of carbonate. Based on the traditional electrokinetic repair method, the chemical precipitation method and electrochemical method are innovatively coupled in this study. Taking the municipal solid waste incineration (MSWI) fly ash produced by a thermal power plant as the research object, an electrokinetic experiment is carried out. By changing the content of sodium carbonate and the voltage gradient, the change laws of electrolyte interface, electrolyte current and Ca2+ concentration are analyzed. Besides, the space–time migration law of soluble Ca2+ in a certain electrokinetic cycle and the carbonate inhibition mechanism are revealed. By means of SEM-EDS and XRD, the elemental composition and micro morphology of fly ash before and after treatment are studied, and the components of precipitation products are determined. The results show that, when the contents of sodium carbonate reach 6.6 % and 9.9 %, the white Ca(OH) 2 floc in the electrolyte can be obviously observed to transform into CaCO 3 precipitation, so as to achieve an ideal inhibition effect. Simultaneously, the influence of voltage gradient on Ca2+ precipitation is greater than that of sodium carbonate. The inhibition mechanism of soluble Ca2+ is mainly through changing the chemical equilibrium of Ca(OH) 2 -CaCO 3 system, and then forming stable CaCO 3 precipitation. [ABSTRACT FROM AUTHOR]

Heterostructured AgBr/Bi 2 Sn 2 O 7 photocatalysts were synthesized successfully via the ultrasonic-assisted chemical precipitation method. XRD, FT-IR, FE-SEM, TEM, XPS, UV–vis-DRS and PL spectroscopy were used to characterize the phase structure, morphology, chemical composition, oxidation state, and optical properties of AgBr/Bi 2 Sn 2 O 7 heterojunction. The photocatalytic activity of as-prepared catalysts was evaluated by the degradation of RhB under visible light irradiation. The obtained AgBr/Bi 2 Sn 2 O 7 composite with the 1:1 molar ratio exhibited significantly enhanced photocatalytic performance. Further first-principles calculations indicated that the hybridization interaction between Ag and O atoms at AgBr/Bi 2 Sn 2 O 7 interface is expected to be beneficial for enhancing the charge transfer and improving the photocatalytic activity of heterostructured composites. [ABSTRACT FROM AUTHOR]

Undoped and Mn 2+ doped CdOZn 3 (PO 4 ) 2 nanocomposites are fruitfully synthesized by chemical precipitation process at room temperature. The morphology, structure and spectroscopic properties of the prepared samples are characterized by X-ray diffraction (XRD), optical absorption, Scanning electron microscope (SEM) with EDS, Fourier transform infrared (FT-IR) spectroscopy, Photolumiscence (PL) and Electron Paramagnetic Resonance (EPR). XRD data confirms the cubic phase of CdO and monoclinic phase of Zn 3 (PO 4 ) 2 . Strain and dislocation density are also calculated from XRD studies. Optical absorption spectrum of Mn 2+ doped CdOZn 3 (PO 4 ) 2 nanocomposite shows different spin-forbidden DMSO- d 6 bands which are the characteristics of octahedral site symmetry related to Mn 2+ . The crystal field parameter Dq and inter electronic repulsion parameters (B and C) are deliberate using optical absorption data. Surface morphology of sample is firm by Using Scanning electron microscopy (SEM) and the distribution of Zn, Cd, phosphate and oxygen species in the prepared sample is identified by EDS. PL studies recognize the white light emission. The ‘g’ value of the nanocomposite material synthesized is lesser than (negative shift) the free electron value (2.0023), which gives ionic nature to the bonding and confirms the presence of Mn 2+ in distorted octahedral site symmetry. [ABSTRACT FROM AUTHOR]

In recent years, transition metal sulfides have been regarded as a promising energy storage material for supercapacitors, due to their high theoretical specific capacity and conductivity compared with other similar metal oxides and hydroxides. However, the sluggish diffusion dynamics and low capacitance impede its practical implement application. Herein, an advanced 3D nanocomposite of NiCo 2 S 4 /CuCo 2 S 4 heterostructure was designed via a time-saving, safe and efficient approach. The mass transfer kinetics of NiCo 2 S 4 /CuCo 2 S 4 nanocomposite has been significantly promoted owing to this novel heterostructure. Therefore, the NiCo 2 S 4 /CuCo 2 S 4 electrode materials reveal a superior specific capacitance (180.8 mAh g−1 at 2 A g−1) and excellent rate properties (84.7% capacitance retention from 2 to 20 A g−1). The asymmetric supercapacitor device assembled with NiCo 2 S 4 /CuCo 2 S 4 and activated carbon has an energy density of 37.0 Wh kg−1 at 400 W kg−1 and outstanding cyclic stability (93.3% remained after 10,000 cycles at 10 A g−1). Density functional theory (DFT) calculation further proves the electronic structure and the charge transfer can be tuned by the heterostructure of NiCo 2 S 4 and CuCo 2 S 4. This work offers a new perspective to design a high-performance electrode material in the field of supercapacitors. [Display omitted] • A 3D NiCo 2 S 4 /CuCo 2 S 4 nanoparticles composite was synthesized by a time-saving chemical deposition method. • NiCo 2 S 4 /CuCo 2 S 4 composite has a larger specific surface area than NiCo 2 S 4 or CuCo 2 S 4. • The heterostructure of NiCo 2 S 4 /CuCo 2 S 4 improves charge transport capacity. • The materials reveal a capacitance (180.8 mAh g−1 at 2 A g−1), rate properties (84.7% retention from 2 to 20 A g−1). [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnO and 3 wt% Tb-ZnO NPs were effectively fabricated by simple chemical co– precipitation method. • Fine-tuning the optical properties of ZnO by Tb ion doping. • The specific surface area was analysed by the single point Brunauer Emmet Teller (BET) for surface area analyzer. • Enhanced the electrochemical sensing behaviour of ZnO/MCPE towards moxifloxacin drug by Tb doping ion doping. • To evaluate the antibacterial activities of pure ZnO and Tb-ZnO NPs. Chemical co-precipitation method was adopted for the synthesize of ZnO and 3 wt% Tb doped ZnO (Tb-ZnO) nanoparticles (NPs) using ascorbic acid as a capping agent and its Optical, photoluminescence, electrochemical-sensing and antibacterial properties were investigated. Formation of hexagonal wurtzite structure was confirmed by XRD studies. FTIR shows strong absorption and stretching vibration between the molecules. The samples morphology was identified by SEM and TEM micrographs. Elemental composition was done by EDXA spectroscopy. S pecific surface area and porosity of Tb-ZnO NPs have been examined by BET method. The influence of Tb content on bandgap was analyzed by UV–Vis spectra; the band gap was originating to be 3.2 and 3.56 eV for undoped ZnO and Tb-ZnO NPs, respectively. PL study confirmed the existence of various types of defects as well as band edges. Electrochemical routines in the direction of moxifloxacin drug were ominously examined via dopant and supplementary results stood established through Tb-ZnO as electrode was made of modified carbon paste (Tb-ZnO/MCPE) by cyclic Voltammetric technique. The antibacterial activities of ZnO and Tb-ZnO NPs were studied by agar well diffusion technique as opposed to pathogenic bacterial strains. [ABSTRACT FROM AUTHOR]

Nano-hydroxyapatite samples with different morphologies were successfully prepared by chemical precipitation method using polyethylene glycol (PEG) as a template. The phase composition, micro-morphology and surface functional groups of the nano-hydroxyapatite samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), respectively. The results reveal that the mirco-morphology of hydroxyapatite can be effectively controlled by adjusting pH values in the preparation. Moreover, the growth mechanism of HAp with different morphologies was also discussed. [ABSTRACT FROM AUTHOR]

Nanocrystalline nickel oxide (NiO), chromium and cobalt doped NiO nanoparticles have been prepared successfully by chemical precipitation method. NiO, Cr and Co-doped NiO nanoparticles have been characterised using various analytical techniques such as X-ray diffraction, FESEM, HRTEM, UV absorption and M-H curves. The average grain size of NiO, Cr and Co-doped NiO nanoparticles are 10.33 nm, 9.54 nm and 8.70 nm respectively. The UV absorbance study shows a strong absorption edge at 314.96 nm, 308.64 nm and 305.37 nm respectively. The band gap values of NiO, Cr and Co-doped NiO nanoparticles are 3.936 eV, 4.017 eV and 4.060 eV. The incorporation of chromium and cobalt into NiO nanoparticles have strongly influenced the magnetic behaviour and the material got converted from super paramagnetic to ferromagnetic material. [ABSTRACT FROM AUTHOR]

Manganese phosphate (Mn(PO)·3HO) nanosheets are successfully fabricated via a facile chemical precipitation method. The Mn(PO)·3HO nanosheets synthesized at 70 °C show excellent supercapacitive performance in 2 M KOH alkaline electrolyte. Typical pseudocapacitance feature of Mn(PO)·3HO nanosheets treated at various annealing temperatures is then evaluated in 2 M KOH alkaline electrolyte. M annealed at 750 °C exhibits the optimal integrated electrochemical properties. Furthermore, an asymmetric supercapacitor composed of M as positive electrode and activated carbon (AC) as negative electrode can reach the high-voltage region of 0-1.7 V. The asymmetric supercapacitor displays high energy density of 32.32 Wh kg and power density of 4250 W kg. The impressive results presented here may pave the way for promising applications in high energy density storage systems. [ABSTRACT FROM AUTHOR]