Agitation Time Research Articles

Sustainable Synthesis of Zeolitic Imidazolate Framework-8 Nanoparticles and Application in the Adsorption of the Drug Chlorhexidine

In an attempt to synthesize nanomaterial concerning chemistry, the sustainable synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles by a low-cost approach through the recycling of waste mother liquors was explored and then indicated the potential to remove chlorhexidine (CHLX) from an aqueous solution. ZIF-8 was produced under solvothermal reaction at 25°C and characterized by Fourier Transform Infrared Spectroscopy, X-ray diffraction, adsorption/desorption of N<sub>2</sub>, dynamic light scattering and contact angle. The water Chemical stability test was conducted using ZIF-8 and it was immersed in pure water for 24 h at room temperature. Batch-type adsorption was used to check the potential of ZIF-8 (first and second generation) for the adsorption of the chlorhexidine with initial chlorhexidine concentration (0.05, 0.06 and 0.07 mol/L), agitation time (1, 3.5 and 6 h) and the mass of nano-adosrbent (0.04, 0.05 and 0.06 g). Process optimization was performed through a Factorial experimental design. The optimum conditions were selected for the nano-adsorbent mass of 0.04 g, agitation time of 1 h and initial chlorhexidine concentration 0.07 mmol/L. The ZIF-8 sustainable synthesis was efficient and generated a crystalline nanomaterial. The result shows that ZIF-8 is stable in water under ambient conditions. The ZIF-8 first generation and ZIF-8 second generation exhibit a high adsorption capacity (27.17 mg/g and 30.96 mg/g). It was found that, under the synthesis conditions, the recycled mother liquor user did not affect the final characteristics of this nanomaterial. The results indicated that the initial concentration of chlorhexidine and nano-adsorbent mass influenced the adsorption capacity. Experimental design provided the process optimum conditions (1 h, 0.04 g of adsorbent mass and 0.07 mmol/L).

Effect of Ultrasonic Agitation Time on Properties of Steel Fiber-Reinforced Investment Casting Shells

Effect of Ultrasonic Agitation Time on Properties of Steel Fiber-Reinforced Investment Casting Shells

Removal of toxic lead from aqueous solution using a low-cost adsorbent

Valorization of waste materials and byproducts as adsorbents is a sustainable approach for water treatment systems. Pottery Granules (PG) without any chemical and thermal modification were used as a low-cost, abundant, and environmentally benign adsorbent against Pb(II), the toxic metal in drinking water. The porous structure and complex mineral composition of PG made it an efficient adsorbent material for Pb(II). The effect of key physicochemical factors was investigated to determine the significance of contact time, PG dose, pH, solution temperature, and coexisting ions, on the process. Pb(II) removal increased by PG dose in the range of 5–15 g/L, and agitation time from 5 to 60 min. Increasing Pb(II) concentration led to a drop in Pb(II) removal, however, adsorption capacity increased significantly as concentration elevated. Pb(II) removal also increased significantly from ~ 45% to ~ 97% by pH from 2 to 12. A ~ 20% improvement in Pb(II) adsorption after rising the solution temperature by 30˚C, indicated the endothermic nature of the process. The sorption was described to be a favorable process in which Pb(II) was adsorbed in a multilayer onto the heterogeneous PG surface. The qmax of 9.47 mg/g obtained by the Langmuir model was superior among many reported low-cost adsorbents. The Pb(II) adsorption was described well by the Pseudo- first-order kinetic model. Na+, Mg2+, Ca2+, Cd2+, and Zn2+ showed a negligible effect on Pb(II) adsorption. However, the presence of Mn2+ and Fe2+ significantly hindered the process efficacy. In conclusion, the use of waste material such as PG against Pb(II) is a viable option from the economic and effectiveness points of view.

Wheat husk-based sorbent as an economical solution for removal of oil spills from sea water

Oil spills are a significant threat to the marine ecosystem that requires immediate removal from the oceanic environment. Many technologies have been employed to clean up oil spills. Of these, adsorption has scored a prominent success due to the high efficiency, economic viability, environmental friendship, and ease of application. The utilization of agricultural waste to produce biosorbents have been considered as an ecofriendly and efficient approach for removing oil. Thus, a new low-cost oil adsorbent was prepared via esterification of the wheat straw (Str) with a hydrophobic benzoyl group, the resulting copolymer (Str-co-Benz) was characterized by FTIR, TGA, DSC, and SEM and used at laboratory scale. The oil spill cleanup process was conducted using a crude oil-natural seawater system under different adsorption conditions such as oil concentration, adsorbent dose, agitation time and speed. Equilibrium studies were performed to determine the capacity of the prepared materials for crude oil adsorption. Langmuir and Freundlich adsorption models were used to describe the experimental isotherms. The reliability of the data was examined and evaluated via application of response surface methodology program. The results showed that oil adsorption followed a pseudo-second-order kinetic model and fitted well with Langmuir model with a maximum adsorption capacity of 10.989 and 12.786 g/g for Str and (Str-co-Benz), respectively. Overall, the modified wheat husk is an effective platform for removing oil from marine ecosystems due to low cost, biodegradability, simple synthesis and fast removal. Moreover, the resulted solid can be used as a fuel in some industrial processes such as steam boilers and brick production incinerators.

Electrolytic galvanizing technology on internal surfaces of machined parts using computer numerical control (CNC)

In the present investigation, the study of the Zinc electrolytic galvanizing process on the interior surfaces for high-pressure pipe couplings is detailed, this through a statistical factorial analysis 23 that allowed to relate the 3 factors of the experimentation layout of parts, electrolyte agitation and immersion time; in this way, 8 types of possible iterations were determined in order to analyze the correlation and the incidence in the quality of the anticorrosive protection under the ISO 10289:2001 standard. The adequate levels of the electrolyte were determined using a Hull cell, and optimal working parameters were established at a temperature of 20 °C, a current density of 2.7 A/dm2 and a voltage of 5 V. After experimentation it was determined that the arrangement of the parts is the most determining factor for the coating to provide good anti-corrosion protection in combination with acid baths. The methodology used could serve as a basis for the collection of new results and possible comparisons.

Synthesis, Characterisation and Utilisation of Magnetic Fe3O4 – TGT Nanocomposite in the Removal of Pb(II) from Aqueous Solutions

Magnetic Adsorption Separation (MAS) method is an ideal substitute for the environmental clean-up process. Magnetic material embedded with natural litter material is a facile route to achieve maximum adsorptive ability at a lower dosage, contact time and increased chance of metal-laden adsorbents’ recovery from aqueous matrices. In the present study, the synthesis of Fe3O4–TGT composite (TGT- C2) by the auto combustion method and its employment for Pb(II) removal from aqueous solutions is discussed. TGT- C2 is characterised using VSM (Vibrating Sample Magnetometer), SEM (Scanning Electron Microscope), Particle Size Analyzer, EDAX (Energy Dispersive X-ray Spectrometer) and FTIR (Fourier Transform Infra Red Spectrophotometer) techniques. TGT- C2 is found to be magnetic in nature and their saturation magnetization (Ms)/ Coercivity (Hc) values are calculated as 1.54 emu g-1/139.83 G, respectively, being less than bare Fe3O4. The synthesised nanocomposite registered a maximum of 98% sequestration of Pb(II) ions under the optimised conditions of 100 mg/L initial metal ion concentration, 10 min agitation time, 50 mg dosage and pH 5 environment. Isothermal verification, the kinetics of adsorption and successive desorption/ regeneration cycles were performed. The outcomes support the preparation of bio-nanocomposites from animal waste was successful in the efficient trapping of divalent metal ions.

Development of dispersive micro solid phase extraction method based on using Fe3O4@UiO-66-NH2@MIP nanocomposite as an efficient and selective sorbent for the extraction of imidacloprid from fruit juice samples

In this study, a magnetic molecularly imprinted polymer (Fe3O4@UiO-66-NH2@MIP) nanocomposite was synthesized for preconcentration, extraction, and selective analysis of imidacloprid using unique characteristics of magnetic iron oxide nanoparticles, metal–organic framework, and molecular imprinted polymer. The synthesized sorbent was investigated using Scanning electron microscopy and Fourier-transform infrared spectroscopy. The results of the characterization analyses ensured the successful synthesis. The relevant optimization parameters such as amount of the sorbent, type and time of agitation, pH, ionic strength, and type and volume of desorption solvent were investigated and optimized. High performance liquid chromatography-tandem mass spectrometry was used in the analysis of the enriched analytes. Under the optimum conditions detection and quantification limits were 0.187 and 0.625 ng/L, respectively. The linear range of 0.625–80 ng/L with a coefficient of determination of 0.9984 was obtained. The obtained results showed that the synthesized sorbent had excellent selectivity for the analyte, good adsorption capacity, high extraction recovery (92.4 %), acceptable stability, and good reusability. Finally, the developed method was successfully applied for the analysis of imidacloprid in different fruit juice samples.

Extraction and enrichment of zinc from chloride media using emulsion liquid membrane: Emulsion stability and demulsification via heating-ultrasonic method

Emulsion liquid membrane (ELM) is highly efficient in heavy metal ion separation from wastewater. However, substantial effort is required to overcome the instability in the process. Hence, this research demonstrates the stability of water-in-oil-in-water (W/O/W) emulsion and demulsification for zinc recovery from chloride media. Iron (III) oxide (Fe2O3) nanoparticles were used as a solid stabilizer in the formation of water-in-oil (W/O) emulsion. Several operating parameters affecting the stability of W/O/W emulsion by means of breakage/swelling and globule size diameter were studied, such as organic-to-internal phase (O/I) ratio, agitation speed, time, and treatment ratio. The most stable formulated W/O/W emulsion was used in the demulsification process using heating-ultrasonic method. The study was conducted by manipulating the temperature, frequency, and time. Meanwhile, experiments on the effect of modifier type, carrier, and stripping agent concentration were carried out for zinc recovery. The most stable W/O/W emulsion was obtained at 1.35:1O/I ratio, 300 rpm agitation speed, 3 min agitation time, and 1:5 treatment ratio. Complete demulsification was achieved at a temperature of 50 °C, 40 kHz frequency, and 210 min contact time. At the best condition of 3% (w/v) 1-octanol, 0.03 M carrier concentration (D2EHPA/Cyanex 302), and 1.375 M acidic thiourea, approximately 93.14% zinc was extracted, and 4.65 times enrichment was obtained in the recovery phase. Hence, it can be concluded that enhancing the stability of emulsion could potentially make ELM applicable in the industry.

Extraction of iron (III) ions by core-shell microgel for in situ formation of iron nanoparticles to reduce harmful pollutants from water

Since the most transition metal ions and organic dyes are hazardous, it is crucial to remove them from water. For this purpose, various systems are reported for removal of only transition metal ions or organic dyes. I have introduced a new system which is suitable for removal of both metal ions and organic dyes. The free radical precipitation polymerization method was used to create the spherical system of silica surrounded by poly(N-vinylcaprolactam-acrylic acid) S@P(NVCP-AA) core shell microgels and then characterized by using FTIR, DLS, XRD, and STEM. The S@P(NVCP-AA) microgel system was applied as adsorbent to extract iron (III) ions from water under various concentrations of S@P(NVCP-AA), iron (III) ions content, pH, and agitation time. The adsorption process of iron (III) ions on S@P(NVCP-AA) microgels was investigated by different adsorption isotherms. The kinetics of adsorption of iron (III) ions on S@P(NVCP-AA) microgel system was also examined by intra-particle diffusion model (InPDM), pseudo-1st order (P1O), pseudo-2nd order (P2O) and Elovich model (EM). Iron nanoparticles were formed by in-situ reduction of iron (III) ions that had been adsorbed in the P(NVCP-AA) shell region of the S@P(NVCP-AA) microgel. The organic pollutants and toxic transition metal ions like 4-nitrophenol (4NiP), methyl red (MeR), methylene blue (MeB) and chromium (VI) ions (CMI) were reduced from an aqueous medium by using the iron nanoparticles loaded in S@P(NVCP-AA) microgels. The pseudo 1st order rate constant values for the catalytic reduction of 4NiP, MeR, MeB and CMI were found to be 0.778 min−1, 0.928 min−1, 0.943 min−1 and 0.142 min−1 respectively. The resulting S@Fe-P(NVCP-AA) system can act as an efficient catalyst for a wide range of additional organic transformations.

Removal of Amoxicillin Antibiotic from Polluted Water by a Magnetic Bionanocomposite Based on Carboxymethyl Tragacanth Gum-Grafted-Polyaniline

Removal of antibiotics from contaminated water is very important because of their harmful effects on the environment and living organisms. This study describes the preparation of a bionanocomposite of carboxymethyl tragacanth gum-grafted-polyaniline and γFe2O3 using an in situ copolymerization method as an effective adsorbent for amoxicillin antibiotic remediation from polluted water. The prepared materials were characterized by several analyses. The vibrating sample magnetometer and thermal gravimetric analysis showed that the carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 bionanocomposite has a magnetization saturation of 25 emu g−1 and thermal stability with a char yield of 34 wt%, respectively. The specific surface area of bionanocomposite of about 8.0794 m2/g was obtained by a Brunauer–Emmett–Teller analysis. The maximum adsorption capacity (909.09 mg/g) of carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 was obtained at pH 7, an agitation time of 20 min, a bioadsorbent dose of 0.005 g, and amoxicillin initial concentration of 400 mg/L. The Freundlich isotherm and pseudo-second-order kinetic models were a better fit with the experimental data. The kinetic model showed that chemical adsorption is the main mechanism for the adsorption of amoxicillin on the bioadsorbent. In addition, the maximum adsorption capacity for amoxicillin compared to other reported adsorbents showed that the prepared bionanocomposite has a higher maximum adsorption capacity than other adsorbents. These results show that carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 would be a favorable bioadsorbent for the remediation of amoxicillin from contaminated water.

Potential Application of Membrane Obtained from Sisal Bagasse in the Removal of Inhibitors from the Fermentation Process

Annual world production of sisal is estimated to be 400,000 tons, but the processing of sisal fiber generates around 160,000 tons of waste per year. The sisal bagasse is discarded, even though it is about 60% carbohydrates in its structure. Therefore, this work seeks to add value to sisal bagasse through the production of cellulose acetate membranes aimed at removing inhibitors from the fermentation process. The membrane was developed using a cellulose acetate polymer synthesized from cellulose isolated from sisal bagasse. Alkaline and acid pre-treatments resulted in 90% pure cellulose. The obtained cellulose acetate was confirmed by infrared spectroscopy. In the synthesis of the membranes, the influence of agitation time and temperature of the bath on the selectivity and porosity were evaluated in four tests, the third condition stood out with porosity of 26.23% and selectivity of 94.51% in the removal of the furfural and 36.62% of the acetic acid.

Enhanced and rapid photocatalytic degradation of toxic dyes by cobalt oxide and modified cobalt oxide under solar light irradiation

A solar light driven photo degradation approach for methylene blue (MB, model molecule of the thiazine dyes class) and malachite green (MG, model molecule of the triphenylmethane category) abatement by Co3O4 and Cr-Co3O4 spinel nanoparticles is reported. The effect of chromium load (5, 10 and 15%) in Co3O4 particles, synthesized by a simple co-precipitation process, was properly studied. The structural and morphological characteristics, chemical composition and optical properties of the materials were investigated by X-ray diffraction (XRD), Transmission Electron Microscopy(TEM), Field Emission Scanning Electron Microscopy – Energy Dispersive Spectroscopy (FE-SEM-EDS), FT-IR spectroscopy, UV–Vis diffuse reflectance spectroscopy (DRS),photoluminescence (PL) and BET surface area analysis. It was observed that properly tuning the initial pH, the initial dye concentration, the agitation time, and the photocatalyst dose, (10)Cr-Co3O4 exhibited an enhanced photocatalytic activity compared to that of pristine Co3O4, demonstrating the positive role of Cr doping In fact, the PL investigation showed that Cr doping in the Co3O4 lattice greatly increase the separation of electron-hole (e−/h+) pairs, whereas the UV DRS spectra and Tauc plot revealed a decrease in the band gap energy for Cr-Co3O4,. The investigations demonstrated that the MB dye degradation increases from 88% to 96% at pH = 11 after doping of Co3Oby 10% of Cr. Similarly, the Cr doping allowed to enhance the MG dye degradation from 85% to 92% at pH = 9. The photo degradation kinetics of both MB and MG dyes by Cr-Co3O4 and Co3O4 NPs were of pseudo-first-order mode. The active species involved in the photocatalytic process were properly identified using various scavengers by trapping holes and radicals. Finally, the photocatalysts showed good stability during recycling maintaining high performances after 5-time usage. .

Modelling and optimization of thermophilic anaerobic digestion using biowaste

Biowaste generation is considerably increasing multiple times recently due to various social and environmental changes like population growth, economic prosperity, globalisation etc. they contain different composition and generated at different stages of their life cycle. Though studies reported for recycle, reproduce and reuse of them, this investigation is unique by focussing to investigate the ideal circumstances for the production of biogas and methane from anaerobic digestion of vegetable waste using response surface methods and artificial neural networks with thermophilic temperature range. Thermophilic temperature of 20.78, organic loading rate of 0.2, pH of 8.81, agitation time of 5.8 and hydro retention time of 3 are the ideal input parameter values for the generation of biogas 3.03 m3 and methane% 186.08 with a desirability of 1. The Response surface model was surpassed by the Artificial Neural Network model.

Removal of Methyl Orange Using Hybrid Spherical Silica Adsorbents

This study investigated the potential of adsorption behaviour of methyl orange onto hybrid spherical silica adsorbent. Removal of dye has been a problem worldwide and the study of removing dye through adsorption method is quite limited. This study aims to synthesize and characterize spherical silica (SSi) adsorbent and evaluate its adsorption capacity of it. The spherical silica adsorbent (SSi) was prepared using oil-in-water (o/w) emulsion polymerization modification where Tetraethyl Orthosilicate (TEOS) acts as the silica precursor. The physicochemical properties of SiNs were characterized using Fourier transform infrared (FTIR), field emission scanning (FESEM), nitrogen adsorption/desorption analysis (NAD), and transmission electron microscopy (TEM). The batch adsorption study for the methyl orange removal parameters such as pH (2-10 ) and agitation time (0-180 minutes). The experimental adsorption data were further evaluated using several adsorption kinetic models, namely pseudo-first-order, pseudo-second-order and Elovich kinetic models. The diffusion kinetics model includes the Weber-Morris plot, Fick’s Law equation and Boyd plot. The result shows that the spherical silica (SSi) adsorbent at pH 2 has the highest adsorption capacity amongst another adsorbent towards methyl orange which is 45.05 mg/g. Furthermore, the equilibrium time for methyl orange adsorption onto SSi was 120 min. The data fitted into a pseudo-second-order kinetic model indicating chemical adsorption, limited by film diffusion.

Plaster board waste (PBW) – A potential fluoride leaching source in soil/water environments and, fluoride immobilization studies using soils

Plaster board waste generated from industries, usually contains major proportion of calcium as calcium sulfate. In addition, fluoride is remarkably one among the constituents of this waste material which leaches off into the soil and aquatic environments and causes fluoride pollution. In order to simulate how the dumping of PBW causes fluoride contamination in soil and water sources, shaking and stirring based batch-mode leaching studies were conducted. These studies explored the leaching of fluoride as a function of particle size, agitation time, pH of the leaching solvent (distilled water), L/S (water: PBW) ratio, temperature and electrolytes. It was explored that 1 g of plaster board waste contains18.54 mg F per gram of PBP. High leaching of 3.72 mg F per liter was studied at pH 6.02 with Ca2+ and TDS contents of 1050 mg L−1 and1640 mg L−1 respectively. The influence of sodium electrolytes such as chloride, nitrate, hydrogen carbonate, carbonate, sulfate, borate, phosphate and acetate on the leaching of fluoride from PBW was studied. The influence of fluoride leaching by sodium phosphate recorded a high value of 12.75 mg L−1 with no detectable amount of calcium ions. The influence of eight electrolytic mixtures each containing five sodium electrolytes on fluoride leaching corroborated the highest leaching in mixtures containing phosphate followed by hydrogen carbonate/carbonate. Solutions of calcium and aluminium chloride and their mixture were used to measure the rate of leachable fluoride in solution. Furthermore, the fluoride leaching at different temperatures and acids was studied. Naturally occurring soils when blended with PBW were observed to immobilize fluoride and lessened the amount of leaching fluoride in water. Various characterization studies such as FTIR, Raman, FESEM (with EDS), XRD and XPS were carried out for PBW and its treated samples using different electrolytes. Fluoride leaching proportionate to the precipitation of carbonate and phosphate was recorded in the case of appropriate electrolyte and mixtures.

Optimizing removal of chromium (VI) ions from water by coagulation process using central composite design: Effectiveness of grape seed as a green coagulant

In the past decades, considerable work has been devoted to remove chromium (VI) ions from the aqueous environment, owning to their serious health concerns to humans and the aquatic ecosystem. Recently, natural coagulants have attracted increasing attention from researchers due to their great ability to remove pollutants from industrial wastewater. In the present study, we focused on the utilization of a grape seed powder (GSP) biocoagulant as low-cost and eco-friendly material for the effective removal of hexavalent chromium, Cr(VI) ions from synthetic wastewater using coagulation process. The GSP was characterized using familiar techniques like phytochemical analysis, scanning electron microscopy (SEM) coupled with EDS mapping, microelectrophoresis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The impacts of some independent parameters such as coagulant dosage, initial pH, initial Cr(VI) concentration, agitation time, and sedimentation time on the removal of Cr(VI) ions by using GSP were examined and the process was optimized by using the response surface methodology (RSM) based central composite design (CCD) design. In addition, the relationship between process variables was described. Results demonstrated that the removal efficiency of Cr(VI) from aqueous solution was decreased by increasing the initial pH of solution and initial Cr(VI) concentration. Furthermore, the removal efficiency is favored by increasing GSP dosage, sedimentation time and agitation time. Optimized values of pH, coagulant dosage, initial Cr(VI) concentration, agitation time and sedimentation time were found to be 4.53, 0.5 g/L, 5.12 mg/L, 15 min and 3.5 h, respectively. The removal mechanism study indicated that the Cr(VI) removal was reached via esterification reaction between the functional groups of GSP and Cr(VI) ions, and reduction reaction of Cr(VI) to Cr(III) species. The high removal capacity validated the effective applicability of GSP as a useful natural coagulant for the removal of Cr(VI) ions from synthetic wastewater.

Impact of agitation time of boar semen doses on sperm traits in short- and long-term extenders

Transport of extended boar semen doses is a common practice in the swine industry. This study aimed to verify the effect of agitation time on sperm parameters during storage in two semen extenders. One normospermic ejaculate from each boar (n = 20) was diluted in a split sample design with long-term (LONG, Androstar® Plus) and short-term (SHORT, Beltsville Thawing Solution) extenders. Extended semen doses were filled with a total volume of 45 mL and 1.5 billion sperm cells and submitted to 0, 3, 6, and 12 h of agitation in an orbital shaker at 70 rpm. The samples were stored at 17 °C for 120 h. Sperm parameters were evaluated for sperm motility, plasma membrane integrity, pH, thermo-resistance test (TRT), oxidative stress status, and mitochondrial membrane potential. Total and progressive motility were affected by the interaction between the agitation time and the extender, with a linear reduction in sperm motility as the agitation time increased for LONG extender (P ≤ 0.05). Semen doses diluted with SHORT showed a higher pH (P < 0.01), and agitation time had a positive quadratic effect with the highest pH observed after 6 h of agitation, regardless of the extender used (P < 0.01). Sperm motility after TRT and plasma membrane integrity potential were not affected by agitation time (P > 0.05). Mitochondrial membrane potential and oxidative stress status quadratically decreased as agitation time increased (P ≤ 0.05). Based on the results, long transport durations of AI doses under mild vibration emissions affect boar semen quality.

Controlling Size Distribution of Silver Nanoparticles using Natural Reducing Agents in MCM‐41@Ag

AbstractIt is by reported the effect of natural reducing agents such as plant extracts (Equisetum myriochaetum leaves, Cymbopogon citratus, Camellia sinensis, Syzygium aromaticum), fruits (orange, apple), and biopolymers (arabic gum, and chitosan) on the size distribution of silver nanoparticles, obtained by green synthesis, to be incorporated in a MCM‐41@Ag nanocomposite. The aim is to determine the influence of temperature, agitation time, concentration, atmosphere, and nature of the reducing agent on the MCM‐41@Ag particle size. According to the DLS analysis, the extract of Syzygium aromaticum produced silver nanoparticles in the range of 8–80 nm. Further structural, morphological, optical, and surface characterization confirmed the obtention of the desired MCM‐41@Ag nanocomposite. Our results show the potential of MCM‐41@Ag to be incorporated in Metal‐insulator‐semiconductor capacitors for detection purposes.

The application of wasteLeucaena leucocephalaseed pods as a bio-based adsorbent for decolourization of solution

AbstractThe adsorption method is widely used in water and wastewater treatment; however, most industrial adsorbents are expensive, limiting the use of the adsorption method in developing countries. Therefore, this study aims at developing a biosorbent from waste Leucaena leucocephala seed pods (LLSP) and apply it (as a cost-effective bio-adsorbent) to remove Janus Green B dye (JGBD) from solutions at different values of pH, agitation time, LLSP dose and JGBD concentration. Different techniques were used to characterize LLSP before and after JGBD removal, including pore size distribution, surface area (SBET) analysis, FTIR, SEM, SPM and the point of zero charges (pHpzc) of the LLSP surface. The results proved that LLSP could remove up to 95% of JGBD at pH, LLSP dose, JGBD concentration and agitation time of 9, 0.08 g/100 ml, 50 mg/l and 30 min, respectively. Langmuir and Freundlich analyses were applied to fit the data for equilibrium biosorption, and it was noticed that the Langmuir isotherm model fits the data, and the full monolayer biosorption ability for JGBD was 142.85 mg/g.

RAW OYSTER SHELL SORBENT FOR REMOVAL OF CONGO RED DYE

Raw oyster shell was successfully prepared as an adsorbent for removing Congo Red (C.R.) dye in an aqueous solution using an adsorption technique. The various parameters influencing this adsorption process, such as adsorbent size, adsorbent dosage, initial dye concentration, contact time, pH, agitation speed and agitation time, were studied. The maximum percentage of dye removal of 96.3% was obtained at the optimised conditions of 75 μm of adsorbent size, 1.0 g of adsorbent dosage, 30 mg/L of initial dye concentration, pH 3, 110 rpm of agitation speed and 75 min of agitation time. The experimental data were analysed using two adsorption models, the Langmuir isotherm model and the Freundlich isotherm model. The adsorption data obtained well fitted for the Langmuir isotherm model indicate a monolayer adsorption reaction involved during the adsorption process. The result shows that raw oyster shells could be employed as a suitable alternative adsorbent to remove Congo red dye in an aqueous solution.Keywords: raw oyster shell, adsorption, congo red