Wet Chemical Precipitation Research Articles

Probing the photocatalytic competency of hydroxyapatite synthesized by solid state and wet chemical precipitation method

In this work, we have demonstrated a comparative investigation on the photocatalytic competency of hydroxyapatite (HAp) prepared by solid state (S-HAp) and wet chemical (W-HAp) precipitation method. Both synthesis protocols utilized eggshell and di-ammonium hydrogen phosphate as the Ca and P precursors respectively while the calcination temperature was fixed at 900 °C. In both cases, X-ray diffraction analysis exposed that the synthetic HAp is biphasic in nature where β-tricalcium phosphate (β-TCP) appeared as the 2nd phase but obviously, the % volume ratio of the later phase was different. Methylene blue (MB), a most accustomed model dye was chosen as the targeted pollutant for photodegradation study and the reaction was carried out using both indoor (simulated sunlight) and outdoor (direct sunlight) irradiation. The photodegradation efficacy of both types of HAp was appraised by monitoring the dye degradation rates. It was clearly noticed that HAp prepared by solid state method triggered the photo-process more actively. S-HAp showed an efficacy of 99.82% under sunlight irradiation and 98.53% under simulated sunlight irradiation (0.2 g S-HAp; 40 ml 10 × 10−6 M MB; pH-9; 120 min irradiation time). On the contrary, W-HAp exhibited only 23.15% efficacy under solar irradiation and 18.76% under simulated sunlight irradiation (0.2 g W-HAp; 40 ml 10 × 10−6 M MB; pH-7; 120 min irradiation time). The reason for greater activity of S-HAp could be the consolidated effect of its inferior crystallinity as well as the capability of generating more active species with the presence of higher percentage of β-TCP.

Synthesis of n‐HAP using different precursors and dependence of Vickers hardness on the structure by tuning sintering temperature

AbstractThree sets of starting materials Ca(NO3)2·4H2O and (NH4)2HPO4; Ca(OH)2 and H3PO4; Ca(OH)2 and (NH4)2HPO4 were chosen for the preparation of different precursors of hydroxyapatite nanoparticles (n‐HAP) by wet chemical precipitation technique denoted by HAP‐1, HAP‐2, HAP‐3. X‐ray diffraction (XRD) studies show that n‐HAP of all three types exhibited single‐phase in the as‐prepared condition. Transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) studies of as‐prepared samples showed characteristic needle‐like particles with a width of 5 nm, which were fully crystalline exhibited by the lattice fringe in HRTEM, and single‐phase demonstrated by SAED patterns. The samples were pelletized and annealed at varying temperatures in the range of 600°C–1400°C. The results indicated that HAP‐1 and HAP‐3 samples showed phase decomposition at 1400°C to form β‐tricalcium phosphate (β‐TCP) while for HAP‐2 no such decomposition occurred up to 1400°C. Data from the Vickers hardness test revealed that the hardness value up to 2.5 GPa was attained at the sintering temperature of 1200°C for HAP‐1 and HAP‐3. The hardness values are consistently higher for HAP‐2 than HAP‐1 and HAP‐3 at all sintering temperatures and attained a value of 3 GPa at 1200°C. Thus, synthesizing n‐HAP by using H3PO4; Ca(OH)2 bestows highest Vickers hardness.

Hydroxyapatite‐Graphene Oxide Nanocomposite with Enhanced Ammonia Sensing Property

AbstractThis study is focused on presenting a new approach for utilizing properties of hydroxyapatite (HAp) and carbon‐containing material in sensing applications. Nanocrystalline HAp and graphene oxide (GO) are synthesized by wet chemical precipitation and Hummer's method, respectively. A nanocomposite based on HAp and 2 wt % concentration of GO is prepared just by a mechanically mixing method. A simple and cost‐effective screen printing technique is utilized for the development of thick films on a glass substrate. The ammonia‐sensing properties of the nanocrystalline material HAp and 2 wt% GO‐doped HAp are investigated by two‐probe electric method. The gas‐sensing parameters like operating temperature, response/recovery time, maximum detection limit, etc., are studied. The best sensing performance is shown by 2 wt% GO doped HAp thick film for the detection of 10 ppm of ammonia at 35 °C, i.e., its operating temperature than the pure HAp. The maximum uptake capacity of ammonia for 2 wt% GO doped HAp is found to be very high, i.e., 2000 ppm compared to the pure HAp, i.e., 1200 ppm. Whereas other parameters like response and recovery time at corresponding operating temperatures are nearly the same for both sensing substrates.

Effect of Yttrium Oxide in Hydroxyapatite Biocomposite Materials: Electrical and Antimicrobial Evaluation

Synthesis and characterization of biocomposite materials of hydroxyapatite (HA) and yttrium oxide (Y2O3) were investigated. HA nanoparticles powder was obtained from mussel shells via a wet chemical precipitation routine. HA powder was doped with 1 and 2 wt% of Y2O3. For microstructural examination, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) coupled with energy dispersive X-rays (EDX) were used. In addition, the dielectric and electrical properties and antimicrobial activities were investigated. XRD patterns reveal the crystallization of the oxyapatite. The peak intensities of pristine HA are inferior compared to the yttrium containing HA composites, thus suggesting that the addition of yttrium promotes the crystallization of HA due to the variance in their ionic radii. FT-IR shows a variation in the phosphate wavenumber, indicating the integration of yttrium into the HA matrix. SEM reveals nanorod- or worm-like crystals arose in clusters. With increasing Y2O3, from 1 to 2 wt%, the DC conductivity reduces from 16 to 9.3 nS/cm, which confirms that high amounts of Y3+ substitute Ca2+ in the HA matrix. In the high-frequency range, the AC conductivity linearly increases with increasing frequency following the universal power law. Further, antimicrobial activity results showed that the addition of yttrium in HA improves the antimicrobial effects against pathogenic bacteria and fungi. Additional research is needed to investigate the doping concentration of yttrium ions, and an anticipated property could be comprehended for several forthcoming biomedical applications.

Influence of RE (Pr3+, Er3+, Nd3+) doping on structural, vibrational and enhanced persistent photocatalytic properties of ZnO nanostructures

Rare earth (RE- Pr, Er and Nd) doped ZnO nanostructures were prepared through simple wet chemical precipitation route. The RE doping induced interesting morphological transition from spherical to flower like structures were analyzed. The X-ray diffraction (XRD) measurements revealed that the prepared materials were of highly crystalline in nature and RE dopant ions did not altered the crystal structure of ZnO. The microstrain of ZnO was altered with respect to the nature of dopants. In the case of the Pr doped ZnO, X-ray photoelectron spectroscopy (XPS) analysis confirmed that the dopant (Pr) ions successfully substituted in the ZnO lattice. Raman spectra revealed RE doping induced lower energy side shift and variation in intensity of the peaks related to the characteristic phonon modes of ZnO. In the case of Nd doped ZnO nanostructures, dopant induced suppression in classical Raman modes and evolution of multiphonon related modes were identified. Optical diffuse reflectance spectral (DRS) measurements, along with the characteristic excitonic band of ZnO, other bands associated to the transitions of 4f energy levels related to the RE ions were observed. The partially filled 4f orbitals led to the enhanced photocatalytic activity in RE doped ZnO nanostructures. The observed enhanced photocatalytic activity in RE doped ZnO when compared to bare ZnO was discussed. The decolorization efficiency of MB ensued the following order 96 > 94 > 86 > 78% for ZnErO, ZnNdO, ZnPrO and ZnO, respectively.

Optical, bio-sensing, and antibacterial studies on Ni-doped ZnO nanorods, fabricated by chemical co-precipitation method

The wet chemical precipitation method has been used to synthesize Zn1-xNixO (x = 0.0, 0.05, 0.1, 0.15, 0.2) nanorods. The morphological and optical properties of Ni-doped ZnO samples annealed at 500 0C are characterized by X-ray diffraction (XRD), reveals that Ni-doped ZnO crystallites were in hexagonal wurtzite crystal structure with secondary phase (NiO) was detected with a sensitivity of XRD measurement with increasing in the dopant concentration (X = 0.1–0.2). The FTIR spectroscopy furnishes additional evidence on functional groups. The outcome scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicated the presence of hexagonal rods like nanostructures. From the BET technique, calculated the pore size distribution and specific surface area of fabricated nanorods. Further, the optical energy bandgap obtained in the series of 3.33–3.11 eV was determined by Kubelka-Munk method. Room temperature photoluminescence (PL) spectra exhibited band edge emission, violet, blue, green, orange, and red emission regardless of the concentration of doping, but intensity increased with levels of Ni2+ ion doping. Cyclic voltammetric (CV) reveals that the Ni incorporation ZnO lattice notably enhanced electrochemical activity with regards to electrochemical sensing of 10 µM uric acid (UA) at a scan rate of 50 mVs−1. Antibacterial studies reveal that the Ni-doped ZnO nanorods possess improved antibacterial activity against both gram-positive (Escherichia coli) and the gram-negative (Enterococcus faecalisis) bacterial strains than the pure ZnO nanorods.

Doping effect of Zn on structural and optical properties of CuO nanostructures prepared by wet chemical precipitation process

CuO exhibits superior properties in semiconducting technology. The preparation with thermal activation can be found in several previous reports. Consequently, the synthesizing process at room temperature is interesting because of no energy consumption, reducing production costs. For material property modification, incorporated metal atoms affect the morphology and properties of the host lattice. Accordingly, the purpose of this work is to study the consequence of Zn doping on the structural and optical properties of CuO, prepared via room temperature synthesizing process of wet chemical precipitation without further calcination. Various analytical techniques studied crystal structure, morphology, chemical composition, and optical properties. X-ray Diffraction (XRD) analysis revealed the formation of a pure monoclinic CuO phase with crystallite size in the range of 25–38 nm. As increasing Zn content, structural and optical properties of doped CuO were changed comparing with pure CuO. Scanning electron microscope (SEM) displayed morphology transformation from irregular plates to nanoparticles. TEM images elucidated the formation of crystals in the different directions of block aggregation. Specific surface area (SSA) revealed a reducing value from 17.2567 to 16.6128 m2/g. PL emission assigned to near band-edge emission at 445 nm and oxygen vacancy existence at 519 nm. Comparison with pristine CuO, PL intensity quenching was found in doped CuO. The reduction of electron-hole recombination corresponds to the increasing energy bandgap with linear tendency, appearing at 2.80–2.94 eV. Finally, this synthesizing route is effective and can extend synthesizing technology to other doped metal oxide nanostructures.

3D Printing of Shrimp Derived Chitosan with HAp as a Bio-Composite Scaffold

ABSTRACT India is the world’s 3rd largest shrimp producer at the same stint the shrimp industry generates 40%–70% waste of the catch volume. In this research, chitosan from shrimp (Penaeus indicus) waste was extracted at 75% degree of deacetylation and was brought down to powder form. Parallelly, a wet chemical precipitation method was adopted to produce hydroxyapatite suspension. The Chitosan powders were blended with the HAp suspension and finally ball milled to achieve composite powders of particle size 0.020 mm having mesoporous nature (3.17 nm) when quantified with BJH model. The scaffold was designed considering four design models namely the hollow cube, dumbbell, dual cone and honeycomb models with 62–67% of porosity. Post FE simulation analysis and design optimization using Pugh’s matrix revealed that the honeycomb model was superior considering the mass (g), porosity (%), compressive stress (MPa) and the level of complexity in mesh array. The composite powders were preheated up to 200°C and then the laser with spot of 0.5 mm width sinters the composite powder forming a scaffold as per design using the Selective Laser Sintering (SLS) process. The final part was subjected to cell viability assay using MG63 osteoblast cell line resulted in an increased cell level on the sixth day.

Whey Proteins-Zinc Oxide Bionanocomposite as Antibacterial Films.

The use of toxic crosslinking agents and reagents in the fabrication of hydrogels is a frequent issue which is particularly concerning for biomedical or food packaging applications. In this study, novel antibacterial bionanocomposite films were obtained through a simple solvent casting technique without using any crosslinking substance. Films were made from a flexible and transparent whey protein matrix containing zinc oxide nanoparticles synthesised via a wet chemical precipitation route. The physicochemical and functional properties of the ZnO nanoparticles and of the composite films were characterised, and their antibacterial activity was tested against S. epidermidis and E. coli. The synthesised ZnO nanoparticles had an average size of about 30 nm and a specific surface area of 49.5 m2/g. The swelling ratio of the bionanocomposite films increased at basic pH, which is an appealing feature in relation to the absorption of chronic wound exudate. A n-ZnO concentration-dependent antibacterial effect was observed for composite films. In particular, marked antibacterial activity was observed against S. epidermidis. Overall, these findings suggest that this novel material can be a promising and sustainable alternative in the design of advanced solutions for wound dressing or food packaging.

Synthesis and characterization of bioinspired nano-hydroxyapatite by wet chemical precipitation

In this work, nanometric hydroxyapatite was added with mineral traces naturally present in mammalian bones. It was synthesized by wet chemical precipitation using Ca(OH)2 obtained from eggshells as a precursor. Subsequent calcination was performed at a low temperature of 250 °C to remove reaction by-products but avoiding the crystal size transition to micrometric sizes. Synthetic hydroxyapatite crystals exhibited irregular-spherical morphologies with a Feret's diameter ranging from 10 to 90 nm. Most importantly, this hydroxyapatite contains levels of Ca, Mg, P, Na, S, Sr, K, Si, Fe, Al, and Ba, close to those reported for mammalian bones. The analysis of the commercial synthetic hydroxyapatite revealed that its crystals form micrometric-like-flakes clusters that do not have additional ions but only Ca and P.

Green Chemistry Synthesis of Nano-Hydroxyapatite : Effect of Natural Stabilisers on Ca/P

Present work described the effect of natural stabilizers on Ca/P on naturally synthesised and Eco-friendly Nano-HAP powders.Nano- powders were preparedemploying wet chemical precipitation method by adjusting Ca/P between 1.5 to2.2,using different Natural Stabilisers (NSs)such as Rice Water (RcW), Soya Milk (SM), Tea Decoction (TD), Tulsi Leaves (TL), Soya Leaves (SL), Rose Petals (RP), Spinach Leaves (SpL), Gum Kondagogu (GKg) and Aloe Vera (AlV)as precursors. The pH of the powders was varying from 8.1 to 12.8.In this paper, the average crystallite sizes of the samples, pH, therate of reaction, initial temperature and Ca/P of synthesised powders are reported.

Assessment of a simple and replicable procedure for selective phosphorus recovery from sewage sludge ashes by wet chemical extraction and precipitation

The selective phosphorus recovery by wet chemical extraction and precipitation was assessed at the laboratory scale aiming at identifying a simple and replicable procedure that could be effectively applied to different types of sewage sludge ashes. The experimental work was performed on five samples of sewage sludge ashes, of which three were obtained from muffle-furnace incineration and two from full-scale mono-incineration plants. A single-step extraction procedure has been investigated by applying different operating conditions (type of leaching acid, liquid-to-solid ratio, contact time). Experimental results indicated that phosphorus recovery efficiency varied between 54 and 92% with limited co-dissolution of metals and metalloids, except for arsenic. Operating conditions, sewage sludge ashes characteristics and phosphorus removal processes in the wastewater treatment plant were the main factors affecting phosphorus recovery efficiency. The application of optimal operating conditions (0.2 M sulfuric acid, liquid-to-solid ratio of 20 and contact time of 2 h) resulted in phosphorus recovery from 76 to 92% on four samples. Subsequently, precipitation of phosphorus from acidic leachate was carried out by lime dosing. After filtering and drying, the recovered products presented a P2O5 content between 11.5 and 36.7% dry weight, with a fraction of soluble phosphorus between 75 and 91%, a good percentage for application as fertilizer or animal feed. Since few undesired elements (i.e., As, Cu and Zn) exceeded the limits for fertilizer application (exception was represented by Ni and Pb, which were present at low concentration), an additional purification step may be required. Overall, experimental results highlighted the influence of process parameters on phosphorus recovery.

Enhanced antifouling property of polydimethylsiloxane-CuO nanocomposite in marine environment

Increased adhesion and biofilm formation by marine microalgae as well as inhibition of settlement of invertebrate larval forms on polydimethylsiloxane (PDMS) foul release coatings is a challenge to overcome. Copper oxide nanoparticles (CuO-NP) were synthesized by a wet chemical precipitation route and incorporated into PDMS foul release surfaces to improve its anti-microfouling nature. In situ antifouling performance of PDMS-CuO nanocomposite (NC) was evaluated in coastal waters and compared with plain PDMS surface. Adhesion and settlement of microalgae and macrofoulers and their succession were monitored for 7 and 90 days respectively. Plain PDMS surfaces were abundantly colonized by microalgae (1.3 × 103 cm−2), wherein significant (p < 0.05) reduction (1.76 × 102) was observed with PDMS-CuO NC. In addition, CuO reinforcement significantly (p < 0.05) reduced the biofouling load and surface area coverage upto 1.6 ± 0.22 Kg m−2 90 day−1 and 27.5 ± 4.5% respectively, whereas plain PDMS surfaces experienced 10.6 ± 1.5 Kg m−2 90 day−1 and 89.6 ± 7.96% respectively. Incorporation of CuO nanoparticles as nanofillers into PDMS matrix offers a promising antifouling alternative to inhibit algal fouling as well as larval settlement by imparting toxicity at the surface through release of metal ions.

Synthesis and characterization of nano-hydroxyapatite added with magnesium obtained by wet chemical precipitation

Biogenic hydroxyapatites from mammalian bones naturally contain traces of ions, like Mg, which play a vital role in the bone remodeling process. In this way, synthetic hydroxyapatites should include this kind of mineral. In this work, hydroxyapatite added with Mg was synthesized by wet precipitation using (NH4)H2PO4, Ca(NO3)2.4H2O, and Mg(NO3)2.6H2O (0, 0.032, 0.061, and 0.123 ​M). Inductively coupled plasma and X-ray diffraction evidenced the Mg inclusion in the hydroxyapatite lattice in the same levels reported for natural hydroxyapatites. The calcination at 600 ​°C was performed to remove the reaction by-products, but it also gave rise to physicochemical changes as the coalescence and crystals recrystallization. It produced, in turn, an improvement in the crystalline quality, according to Raman analysis. Despite those physicochemical changes, all the samples remained nanometric according to scanning electron microscopy imaging.

RETRACTED ARTICLE: Synthesis and characterization of magnetite/hydroxyapatite nanoparticles for biomedical applications

During the last few decade, magnetite/hydroxyapatite nanoparticles have attracted much attention for its potential applications in the field of medicine and controlled drug delivery. In the present work, we have intended and synthesized, magnetite/hydroxyapatite nanoparticles by wet-chemical precipitation route. The thermal decomposition of the prepared sample was carried out by Thermogravimetric and Differential Scanning Calorimetry (TG/DSC) analysis upto 1000 °C, it showed that the sample was stable up to 919.2 °C. The phase formation, functional groups, morphology and magnetic property of as-prepared and annealed samples were characterized using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), micro Raman, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission electron microscopy (TEM) and vibrating-sample magnetometer (VSM). By adopting Scherer method detailed structural analysis like the crystallite size, strain, dislocation density, lattice parameter, unit cell volume, surface area and fraction of crystallinity were calculated for as-prepared and annealed HAP samples. The average crystallite size of the as-prepared, annealed at 700 °C, 800 °C and 900 °C are 39, 46, 51 and 65 nm, respectively. The dislocation density, strain and surface area were decreased. FT-IR and Raman spectra showed both as-prepared and annealed samples possessed the characteristic bands of HAP. FE-SEM and TEM images depicted and confirmed the morphological characteristics of HAP. The VSM analysis confirmed that both as-prepared and annealed samples of HAP are in diamagnetic nature. The dielectric constant of as-prepared and annealed samples decreased with increase in annealing temperature whereas the conductivity increases with increase in frequency. The antibacterial property of apatite samples depending on the types of bacterial strains and also activity changed with the crystallite size.

Hydroxyapatite Coatings on Calcite Powder for the Removal of Heavy Metals from Contaminated Water

An approach for the remediation of heavy metal-contaminated wastewater that is gaining increasing attention is the application of hydroxyapatite (HAP)-based particles. HAP is conventionally synthesized through wet chemical precipitation of calcium and phosphate ions, although later studies have focused on HAP synthesis from solid calcite contacted with a phosphate solution under ambient conditions. This synthesis route can allow saving soluble Ca-chemicals and, thus, make the process more cost-efficient. The aim of this study was to coat natural calcite powder with a layer of HAP for the removal of Zn and Cu from contaminated water. For this purpose, a HAP layer was synthesized on calcite particles, characterized using several complementary techniques and evaluated for the removal of Zn and Cu from synthetic solutions. Sorption kinetics and equilibrium isotherms, as well as the effect of sonication of the synthesized sample on its sorption performance, were determined. The results showed that calcite particles were efficiently coated with a HAP layer with high capacity in removing Zn and Cu from acidic solutions, with a qmax of 34.97 mg/g for Zn (increased to 37.88 g/mg after sonication of the sample) and 60.24 mg/g for Cu (which hardly varied with sonication). The mechanisms behind the sorption of Zn and Cu onto HAP, inferred from pH changes, the relation between metal uptake and Ca2+ release and XRD analysis, included surface complexation, ion exchange and precipitation of new Zn- and Cu-containing phases.

Methylene Blue Dye Adsorption from Wastewater Using Hydroxyapatite/Gold Nanocomposite: Kinetic and Thermodynamics Studies.

The present work demonstrates the development of hydroxyapatite (HA)/gold (Au) nanocomposites to increase the adsorption of methylene blue (MB) dye from the wastewater. HA nanopowder was prepared via a wet chemical precipitation method by means of Ca(OH)2 and H3PO4 as starting materials. The biosynthesis of gold nanoparticles (AuNPs) has been reported for the first time by using the plant extract of Acrocarpus fraxinifolius. Finally, the as-prepared HA nanopowder was mixed with an optimized AuNPs solution to produce HA/Au nanocomposite. The prepared HA/Au nanocomposite was studied by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) analysis. Adsorption studies were executed by batch experiments on the synthesized composite. The effect of the amount of adsorbent, pH, dye concentration and temperature was studied. Pseudo-first-order and pseudo-second-order models were used to fit the kinetic data and the kinetic modeling results reflected that the experimental data is perfectly matched with the pseudo-first-order kinetic model. The dye adsorbed waste materials have also been investigated against Pseudomonas aeruginosa, Micrococcus luteus, and Staphylococcus aureus bacteria by the agar well diffusion method. The inhibition zones of dye adsorbed samples are more or less the same as compared to as-prepared samples. The results so obtained indicates the suitability of the synthesized sample to be exploited as an adsorbent for effective treatment of MB dye from wastewater and dye adsorbed waste as an effective antibacterial agent from an economic point of view.

Study of UV-sensitive Ag doped WO3 prepared using ultra-sonification

In this research work, authors have investigated optical and structural properties of silver doped tungsten oxide. The method used for preparation of samples is rapid, easy and prolific wet chemical precipitation synthesis technique with novel feature of ultrasonification. A series of samples with varying concentration of dopant was prepared and characterized using different sophisticated instruments. X-Ray Diffraction (XRD) reveal formation of hexagonal crystal structures with an average crystallite size of 25 nm. TEM images show square and rectangular nanoplates with silver nanoparticles deposited on them in case of pure and Ag doped tungsten oxide respectively. A considerable decrease in band gap in Ag doped WO3 was observed with the increase in doping concentration(0.1, 0.25, 0.5, 0.75 and 1 mmol). UV-Rays with wavelength ranging from 225 nm to 400 nm were completely absorbed and blue emission was obtained from as-synthesized nanocomposites when excited by 325 nm ultraviolet light. This novel property of Ag doped WO3 shows great potential in preparation of UV-light sensitive “smart glasses”.

Proposed Industrial Scale Setup for Production of ZnO Nanoparticles Using Wet Chemical Synthesis Method

In this study, an industrial method is provided for the synthesis of zinc oxide (ZnO) nanoparticles by a simple and economical wet chemical precipitation reaction between Zinc Chloride (ZnCl2) and Sodium Hydroxide (NaOH) at low temperatures less than 80 °C. In first step, Small quantity of ZnO powder is produced in laboratory scale. As-synthesized lab-scale ZnO powders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Orthogonal experiments were performed to find out the optimal conditions for the maximum yield of ZnO powder. In second step, the process flow diagram (PFD), material &amp; energy balance and design of reactor were done on the basis of lab-scale data. Overall, this research work proposes that ZnO powder can be manufactured easy and economical method which can be used for various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic etc.

Mg(OH)2 nanostructures using impure brine: optimization of synthesis parameters by Taguchi robust design and study of optical properties

In this research, high purity magnesium hydroxide (Mg(OH)2) nanoparticles were successfully synthesized by the wet chemical precipitation method from an impure precursor. The effective parameters of the synthesis to achieve magnesium hydroxide nanoparticles with smaller crystallite sizes such as the precipitator agent concentration, the reaction temperature, the amount of surfactant, and the suspension aging time were studied. Optimum conditions were determined by using the Taguchi design method. Each of these factors was investigated in three levels. The analysis of variance (ANOVA) was exploited to determine the contribution of various process parameters on the response. Statistical analysis results indicate that among investigated parameters, the reaction temperature, as well as the suspension aging time, has the most effect on the magnesium hydroxide nanoparticles’ crystallite size. Additionally, there is reasonable accordance between the predicted crystallite average size (17.14 ± 3.1 nm) and the obtained crystallite average size in optimum conditions (19.22 nm). Structural and phase investigations, the chemical composition, as well as optical and morphological properties of synthesized nanoparticles, were precisely investigated through XRD, EDS, FESEM, TEM, FTIR, and UV–Vis. The synthesized sample in optimum conditions had a wide optical band gap due to the smallest crystallite size.