Shaking Time Research Articles

Optimization of the Deproteinization Process via Response Surface Methodology, Preliminary Characterization, and the Determination of the Antioxidant Activities of Polysaccharides from Vitis vinifera L. SuoSuo.

In this study, the response surface method (RSM) was used to optimize the deproteinization process of polysaccharides from Vitis vinifera L. SuoSuo (VTP). The antioxidant capacities of polysaccharides before and after deproteinization were evaluated. The structure of deproteinized VTP (DVTP), which has relatively strong antioxidant activity, was characterized, and the protective effect of DVTP on H2O2-induced HT22 cell damage was evaluated. The results of the RSM experiment revealed that the ideal parameters for deproteinization included a chloroform/n-butanol ratio (v/v) of 4.6:1, a polysaccharide/Sevage reagent (v/v) ratio of 2:1, a shaking time of 25 min, and five rounds of deproteinization. Preliminary characterization revealed that the DVTP was an acidic heteropolysaccharide composed of seven monosaccharides, among which the molar ratio of galacturonic acid was 40.65. FT-IR and the determination of uronic acid content revealed that DVTP contained abundant uronic acid and that the content was greater than that of VTP. In vitro, the antioxidant activity assay revealed that the hydroxyl radical scavenging capacity and total antioxidant capacity of DVTP were greater than those of VTP. In the range of 0.6~0.8 mg/mL, the DPPH scavenging capacities of VTP and DVTP were greater than that of vitamin C. In addition, cell viability was measured via a CCK-8 assay, which revealed that DVTP had a strong defense effect on H2O2-induced damage to HT22 cells. These findings suggest that DVTP has high antioxidant activity and could be used as a natural antioxidant in functional foods and medicines.

Batch and column studies for the removal of basic red-46 dye and textile by using magnesium oxide (MgO), strontium titanium trioxide (SrTiO3), cobalt- and iron-doped lanthanum chromium trioxide (Co.Fe.LaCrO3), and cadmium sulfide (CdS)-doped graphene oxide nanocomposites.

Despite efforts to reduce the risk of toxic chemicals, colors, and dyes being released into the environment from urban and industrial areas, there is still cause for concern. Colored water must be filtered and sterilized before it can be used for irrigation. The utilization of metal oxide and nanocomposite materials in wastewater treatment procedures appears to be a viable option for the future. Therefore, different compounds were doped with graphene oxide to identify the best material for dye removal by the adsorption process. According to recent studies, the ideal conditions for graphene oxide-doped magnesium oxide (GO/MgO) are as follows: pH 10 showed the highest adsorption capacity (qe) at 49.4mg/g; an adsorbent dosage of 0.01g/50mL showed 48.3mg/g qe; a shaking time of 30min resulted in 44.2mg/g qe; an initial dye concentration of 100mg/L yielded 53.6mg/g qe; and a temperature of 35°C gave 49.5mg/g qe. For graphene oxide-doped strontium titanate (GO/SrTiO3), the optimum conditions were as follows: pH 10 with 45.8mg/g qe; an adsorbent dose of 0.01g/50mL with 40.5mg/g qe; a shaking time of 30min with 75mg/g qe; and a temperature of 35°C with 44.7mg/g qe. Graphene oxide-doped cobalt and iron-doped lanthanum chromium titanate (GO/Co.Fe.LaCrO3) showed optimum conditions of pH 9 with 34.2mg/g qe; an adsorbent dose of 0.01g/50mL with 27.5mg/g qe; a shaking time of 45min with 33.2mg/g qe; an initial dye concentration of 100mg/L with 37.6mg/g qe; and a temperature of 35°C with 42.5mg/g qe. Graphene oxide-doped cadmium sulfide (GO/CdS) showed the following optimum conditions: pH 8 with 23.1mg/g qe; an adsorbent dose of 0.01g/50mL with 25.5mg/g qe; an initial dye concentration of 75mg/L with 28.3mg/g qe; and a temperature of 35°C with 33.5mg/g qe. The pseudo-first-order model was the best fit only for graphene oxide-doped magnesium oxide (GO/MgO) with an R2 value of 0.966, while the pseudo-second-order adsorption isotherm was the best fit for all four products, with R2 values ranging from 0.991 to 0.998. Additionally, the Langmuir adsorption isotherms provided good results for all four products, with R2 values ranging from 0.957 to 0.985. The Freundlich adsorption kinetics showed satisfactory fit only for graphene oxide-doped magnesium oxide (GO/MgO) and graphene oxide-doped cadmium sulfide (GO/CdS), with R2 values of 0.951 and 0.982, respectively. To examine the characteristics and practicality of the adsorption process, certain thermodynamic variables were calculated. The adsorption capability of the most efficient nanocomposites for the degradation of basic red-46 was significantly affected by various concentrations of heavy metal ions and electrolytes. In dye solutions containing surfactants/detergents, the adsorption efficiency of several effective photocatalysts for basic dyes was significantly reduced. A 0.5M HCl solution was found to be the most effective for desorption. In column investigations, the optimal bed height, flow velocity, and dye intake levels were determined to be 3cm, 1.8mL/min, and 70mg/L, respectively, for maximal adsorption of basic red-46. The adsorption investigation of genuine textile waste products has also been carried out to facilitate the practical deployment of this approach. The methods used in this study were cost-effective, easy to handle, and eco-friendly and involved no hazardous materials in the synthesis, making the resulting materials non-hazardous. All these methods were part of green chemistry.

Biosynthesis Optimization of Antibacterial-Magnetic Iron Oxide Nanoparticles from Bacillus megaterium.

The occurrence of antibiotic resistance on common bacterial agents and the need to use new generations of antibiotics have led to the use of various strategies for production. Taking inspiration from nature, using bio-imitation patterns, in addition to the low cost of production, is advantageous and highly accurate. In this research, we were able to control the temperature, shake, and synthesis time of the synthesis conditions of Bacillus megaterium bacteria as a model for the synthesis of magnetic iron nanoparticles and optimize the ratio of reducing salt to bacterial regenerating agents as well as the concentration of salt to create iron oxide nanoparticles with more favorable properties and produced with more antibacterial properties. Bacterial growth was investigated by changing the incubation times of pre-culture and overnight culture in the range of the logarithmic phase. The synthesis time, salt ratio, and concentration were optimized to achieve the size, charge, colloidal stability, and magnetic and antibacterial properties of nanoparticles. The amount of the effective substance produced by the bacteria was selected by measuring the amount of the active substance synthesized using the free radical reduction (DPPH) method. With the help of DPPH, the duration of the synthesis was determined to be one week. Characterizations such as UV-vis spectroscopy, FTIR, FESEM, X-ray, and scattering optical dynamics were performed and showed that the nanoparticles synthesized with a salt concentration of 80mM and a bacterial suspension to salt ratio of 2:1 are smaller in size and have a light scattering index, a PDI index close to 0.1, and a greater amount of reducing salt used in the reaction during one week compared to other samples. Moreover, they had more antibacterial properties than the concentration of 100mM. As a result, better characteristics and more antibacterial properties than common antibiotics were created on E. coli and Bacillus cereus.

Efficient adsorption of amoxicillin onto silica nanoparticles synthesized from rice husks

The objective of the present study is to prepare bio silica nanoparticles (SN) from rice husks as a biomass agricultural solid waste material. The synthesized silica nanoparticle was investigated with different tools such as TGA, XRD, SEM, TEM, nitrogen gas adsorption, and FTIR. Adsorption of amoxicillin was studied under different application conditions such as the effect of dosage of adsorbent, medium acidity, time of shaking, initial amoxicillin concentration, and the effect of temperature. Characterization techniques showed that SN is characterized by a high surface area (529.2 m2/g), small pore radius (1.32 nm), thermal stability, and particle size within range of 20–25 nm as calculated from TEM analysis. Adsorption of amoxicillin onto SN followed PSO kinetic models and well fitted with Temkin, van ‘t Hoff, and Langmuir linear models with maximum adsorption capacity reached 99.8 mg/g at 38 °C. The adsorption process is endothermic and spontaneous, as shown by thermodynamic characteristics. Desorption and reusability studies confirmed that acetone is the most efficient desorbing agent with 97.1% desorption efficiency. While reusability of solid adsorbent after six cycles of adsorption and desorption of amoxicillin is reduced by only 7.1%.

Endocuff Vision-Assisted Resection for Difficult Colonic Lesions-Preliminary Results of a Multicenter, Prospective Randomized Pilot Study.

Background-Screening programs for colorectal cancer are implemented due to their ability to reduce mortality. The Endocuff Vision is a new endoscopic device that significantly improves the adenoma detection rate. The primary outcome was to assess the efficacy of ECV in improving stability and reducing operation time during difficult colon polypectomies in a multicenter randomized prospective study. Methods-In a randomized multicenter pilot study, two groups of patients who underwent difficult polypectomies with and without the assistance of Endocuff Vision were compared. Demographics and clinical characteristics of patients were obtained, and polyps' size, morphology, site, and access (SMSA); polypectomy time; and endoscope stability were evaluated. Results-From October 2016 to April 2020, 32 patients were enrolled. In total, 12 patients underwent Endocuff Vision polypectomy, and 20 patients underwent standard polypectomy by using a computer-generated random number table. No statistical differences were found in clinical characteristics, SMSA, and polypectomy time. The most interesting findings were the positive correlations between shaking and SMSA (r = 0.55, p = 0.005) and shaking and polypectomy time (r = 0.745, p < 0.0001). Conclusion-Endocuff Vision seems to be adequately stable during difficult endoscopic resection procedures. The new parameter proposed that shaking is strongly correlated to the stability of the endoscope, the difficulty of the resection (SMSA), and the polypectomy time.

ASSESSING THE EFFICIENCY OF CEMENT KILN DUST FOR HEAVY METALS REMOVAL FROM SIMULATED POLLUTED WATER

Heavy metal contamination in the environment is unavoidable issue. Heavy metals directly influence human being lives since they concentrate in the food cycle, even in low amounts. Some heavy metals pollute the water resources, in dangerous limits for human life. The current study suggested the cement kiln dust (CKD) as a low-cost and effective adsorbent to remove heavy metals ions from solutions. Therefore, the study investigated the copper, lead and cadmium removal from aqueous solution by cement kiln dust (CKD) as industrial by-product. The laboratory experiment included two factors. The first factor consists of three different diameter particles i.e., 50,100, and 150 . While the second factor included three concentrations of each of copper, cadmium, and lead ions namely 50,100, and 200 mg. l-1. The cement kiln dust was identified by X-ray diffraction analysis (XRD) to determine its chemical characteristics. Also, pH and EC were measured for the cement kiln dust solution. Before the study starting, the initial concentration of the copper, cadmium, and lead were measured in the CKD power. The study was conducted at temperature of 25 . The removal efficiency was calculated at two different time of shaking, namely 1 and 2 hours. The obtained results indicated that CKD can be used as a low cost and effective sorbent for copper, cadmium, and lead ions from polluted water. Moreover, the results show that the high pH and high surface area for the cement kiln dust have the main effect of making the CKD efficient adsorbent material.

A novel control strategy for reproducing the floor motions of high-rise buildings by earthquake-simulating shake tables

To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters (EDPs), a three-layer testbed named Nonstructural Element Simulator on Shake Table (NEST) has been developed. The testbed consists of three consecutive floors of steel structure. The bottom two floors provide a space to accommodate a full-scale room. To fully explore the flexibility of NEST, we propose a novel control strategy to generate the required shake table input time histories for the testbed to track the target floor motions of the buildings of interest with high accuracy. The control strategy contains two parts: an inverse dynamic compensation via simulation of feedback control systems (IDCS) algorithm and an offline iteration procedure based on a refined nonlinear numerical model of the testbed. The key aspects of the control strategy were introduced in this paper. Experimental tests were conducted to simulate the seismic responses of a full-scale office room on the 21st floor of a 42-story high-rise building. The test results show that the proposed control strategy can reproduce the target floor motions of the building of interest with less than 20% errors within the specified frequency range.

Development of the QuEChERS Extraction Method for the Determination of Polychlorinated Biphenyls (Aroclor 1254) in Soil Samples by Using GC-MS

Polychlorinated biphenyls (PCBs) have been found in soil, which has typically been the result of industrial pollution in the past two decades. Although they are banned, PCBs can still be found in soils and other environmental media. For this reason, it is critical to develop an analytical method that can reliably identify and monitor their sources. This study describes a gas chromatography with mass spectrometry (GC-MS) technique, which was used to detect PCBs in soil samples by using a fast extraction method. Using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, PCBs were more effectively extracted from soil. Different related parameters, such as time of shaking and centrifuging, type of solvent, and clean-up adsorbents, were compared and optimized. As the extraction solvent, acetonitrile/water produced the best results, and as the dispersive solid-phase extraction sorbent, diatomaceous earth produced the best results. Procedures allowed recovery values between 95.3% and 103.2%. A limit of detection of 1.9 µg/kg was determined with relative standard deviations (n = 3) of 2.1–4.0% for intra-day assays and 3.6–5.8% for inter-day assays. It was demonstrated that the method was simple, sensitive, efficient, and environmentally friendly when applied to soil samples. To our knowledge, an integrated approach based on QuEChERS for the determination of Aroclor 1254 in soil has not been published before. It is believed that this approach will eliminate the significant challenge of sample extraction in GC-MS processing, which was considered to be a procedural challenge in previous analyses.

Stability evaluation of circular tunnels in cohesive frictional soil under earthquake loading using the modified pseudo-dynamic approach

The peripheral stability of tunnels is maintained by installing support systems in the form of linings. The required resistance of the linings depends on the stresses exerted by the surrounding medium. This study evaluated the support pressure of the lining for circular tunnels in cohesive-frictional soil under earthquake loading by applying the modified pseudo-dynamic approach in the finite element lower bound limit analysis framework. The normal stresses exerted by the surrounding soil vary along the tunnel's periphery, and the tunnel's stability is ensured when the minimum support pressure offered by the tunnel lining is equal to or greater than the maximum normal stress exerted by the soil at the ultimate failure condition. The horizontal and vertical earthquake accelerations, amplitude, and phase of the accelerations were varied with depth by satisfying the stress boundary conditions. The shear strength parameters of soil (cohesion and friction angle), tunnel cover and its diameter, and the parameters owing to an event of an earthquake (acceleration, frequency of primary and shear waves, and the time of shaking) influence the magnitude and location of maximum normal stress along the tunnel's periphery.

Utilizing modified cellulose nanoparticles derived from a plant loofah sponge to improve the removal of diazinon insecticide from an aqueous medium.

Organophosphate insecticides, such as diazinon, have been well investigated to pose health and environmental risks. In this study, ferric-modified nanocellulose composite (FCN) and nanocellulose particles (CN) based on a natural source as a loofah sponge were synthesized to verify their adsorption potential to eliminate diazinon (DZ) from contaminated water. The as-prepared adsorbents were characterized by performing TGA, XRD, FTIR spectroscopy, SEM, TEM, pHPZC, and BET analyses, in which FCN showed high thermal stability, surface area of 82.65 m2 g-1, surface with mesopores, good crystallinity (61.6%), and particle size of 86.0 nm. The results of adsorption tests demonstrated that the maximum Langmuir adsorption capacity (294.98 mg g-1) was exhibited by FCN at 38 °C, pH 7, 1.0 g L-1 of adsorbent dosage, and 20 h of contact shaking time. The effect of adding KCl solution with high ionic strength (1.0 mol L-1) reduced the DZ removal percent by 52.9%. The experimental adsorption data achieved the best fit with all the applied isotherm models with favorable, physical, and endothermic nature of adsorption consistent with thermodynamic data. Pentanol attained higher desorption efficiency (95%) and was used in five adsorption/desorption cycles in which FCN exhibited only an 8.8% decrease in the removal percent of DZ.

Extraction optimization of anti-Parkinson’s medication L-DOPA and bioactive compounds from Mucuna atropurpurea (Roxb.) Wight & Arn. with biomedical potential: RSM based desirability function approach

A statistical optimization tool, Central Composite Design (CCD) part of Response Surface design with the aid of the desirability function (DF) approach was employed to optimize and intensify the anti-Parkinson’s medicine L-3, 4-dihydroxyphenylalanine (L-DOPA), and bio-constituents extraction from Mucuna atropurpurea. The antioxidant and anti-inflammatory activities of an optimized plant extract were measured systematically using a series of assays to determine their relationship with total phenolic and flavonoid contents. Following multiple regression analyses of the experimental results, the optimal conditions were found for the maximum extraction of L-DOPA (112.68 mg/g), TPC (66.505 mgGAE/g), and TFC (132.44 mgQUE/g) were 10.35 min of ultrasonication time, 5.55 h of incubation (shaking) time with 52 °C of extraction temperature. The L-DOPA content was quantified using validated RP-HPLC under the optimized conditions. An estimate of the ANOVA and fit statistics “Suggested” the Quadratic polynomial model fit satisfactory. Validated response surface plots (Ramp function, cube plot, and bar graph of desirability) were the confirmation outputs showing significance to the target response. In conclusion, RSM provides the measures of the influence of factors on each quality characteristic to achieve actual outcomes at the optimal settings and model fit. It also revealed that a multi-target strategy consisting of L-DOPA therapy, antioxidants, iron chelation, and anti-inflammatory properties of Mucuna atropurpurea may provide a targeted new approach toward neuroprotection in Parkinson’s disease. The approach proposed in this research proved to be robust and reliable for L-DOPA investigations, demonstrating its enormous potential for industrial applications.

Multivariate Nonconformity Analysis for Paving Stone Manufacturing Process Improvement

Abstract The article presents the result of multidimensional analysis of ‘Behaton’ type paving stones’ nonconformities for improving the production process by improving the quality of the final product. Statistical tools, including SPC tools and quality tools, both basic and new, were used to analyse nonconformities in the spatial-temporal system, i.e. according to the type of nonconformity and according to the examined months. The purpose of using the data analysis tools was to thoroughly analyse the cases of nonconformities of the tested product, obtain information on the structure of these nonconformities in the various terms, and information on the stability and predictability of the numerical structure of nonconformity over time. Potential causes influencing a large percentage of paving stone defects were identified, factors and variables influencing the most frequently occurring nonconformities were determined, and improvement actions were proposed. As a result of the multidimensional and multifaceted analyses of paving stone nonconformities, it was shown that in the structure of nonconformity there were cases that were unusual in terms of the number of occurrences, and the lack of stability in the number of nonconformities in terms of the examined months was proven. Three critical nonconformities of the tested product were identified: side surface defects, vertical edge defects, and scratches and cracks. It was determined that the most important factor causing a large percentage of nonconformity was the time of shaking and vibrating the concrete, which was significantly related to the technical condition of the machines, and the most important reason for a large percentage of paving stone nonconformity was the lack of efficient maintenance. Machine, method, and man turned out to be the most important categories of problem factors and specific remedial actions were proposed. A multidimensional look at the structure of paving stone nonconformity as well as the factor and causes causing them has brought a lot of valuable information for the management staff of the analysed company, thanks to which it is possible to improve the production process and improve the quality of the final product.

Removal of Cr(VI) and Ag(I) by grafted magnetic zeolite/chitosan for water purification: Synthesis and adsorption mechanism

In this paper, a novel grafted zeolite/Fe3O4/chitosan (ZMC-MAH-TEPA) adsorbent was greenly synthesized and evaluated for the removal of Cr(VI) and Ag(I) in single and bi-component solutions. The characterization data of XRF, XRD, FT-IR, VSM, TGA, BET and SEM showed the successful fabrication of the adsorbent with abundant -NH2 and -NH- as well as great recovery properties (11.70 emu/g). The effects of experimental parameters, including pH value, initial concentration, temperature, time, and coexisting ions on single and bi-component adsorption, were investigated. The results demonstrated that the adsorption capacities increased with the enhanced shaking time and concentration until equilibrium was reached. The optimum pH value was 3 for Cr(VI) adsorption and 5 for Ag(I) adsorption. The maximum adsorption capacities for Cr(VI) and Ag(I) ions, obtained by the Langmuir model, were 50.75 and 70.12 mg·g−1 in single metal solutions and 45.45 and 58.94 mg·g−1 in bi-component metal solutions (Cr(VI)/Ag(I) = 1:1), respectively. Additionally, the adsorption mechanism of Cr(VI) and Ag(I) was explained in terms of electrostatic interaction and hydrogen bonding between metal ions and -NH2 and -NH- in ZMC-MAH-TEPA. Taken together, this study provides a clean approach to synthesizing chitosan-based adsorbents for the efficient removal of Cr(VI) and Ag(I) ions.

Comparison of microscopic adsorption characteristics of Zn(II), Pb(II), and Cu(II) on kaolinite

In this research, kaolinite was used to investigate the comparative adsorption of copper, lead, and zinc ions through batch control experiments and first principles calculations. Different adsorption conditions were considered as the effect of solution acidity, initial concentration of ions, and contact shaking time. The adsorption system isotherms and kinetic studies were better agreed with the Langmuir and pseudo-second-order kinetic models. They reached adsorption equilibrium within two hours and maximum adsorption capacities of Zn(II), Pb(II), and Cu(II) on kaolinite were 15.515, 61.523, and 44.659 mg/g, respectively. In addition, the microscopic adsorption changes of Zn(II), Pb(II), and Cu(II) on kaolinite were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The results showed that Zn(II), Pb(II), and Cu(II) were most likely to be adsorbed on the kaolinite surface. Furthermore, the adsorption mechanism of [Zn(OH)]+, [Pb(OH)]+, and [Cu(OH)]+ on the kaolinite (001) surface was systematically studied through first-principles density functional calculations. The adsorption characteristics of different ions were evaluated by calculating the adsorption energy of the equilibrium adsorption configuration, state density, and electron density. The adsorption energy of [Zn(OH)]+, [Pb(OH)]+, and [Cu(OH)]+ were − 0.49, − 1.17, and − 1.64 eV, respectively. The simulation results indicated that new hybrid orbitals were formed between the metal ions and O atoms on the kaolinite surface, with electron transfer occurring the adsorption processes. The charge transfer direction for [Pb(OH)]+ was opposite those for [Zn(OH)]+ and [Cu(OH)]+. [Zn(OH)]+ was more likely to form polydentate complexes with hydroxyl groups on the kaolinite surface than [Cu(OH)]+ and [Pb(OH)]+. This work further elucidated the interaction mechanism between the adsorption systems and provided fundamental theoretical support for the structural modification and optimization of kaolinite, such as increasing the layer spacing of kaolinite and introducing other active groups on its surface to improve the adsorption capacity of heavy metal ions in water treatment and soil remediation.

Novel laboratory extraction method using magnetically micro bubble stream

Innovative, sensitive and accurate method for liquid-liquid extraction using bubble phenomenon. is presented in this work. A working system was designed, consisting of two basic parts: the pump air to generate the bubbles and the pump device, to pump or withdraw the organic layer from the liquid-liquid system key variables study was performed in the system containg Dithizone (0.001 M) in CHCl₃ solvent and aqueous copper (II) chloride (1000 ppm) solution to find out the extent of their impact on the extraction performance obtained in this way. The effect of copper concentration in the initial sample, shake time, size of bubbles flowrate were studied, fixing the optimal conditions: for a sample of (10 mL) aqueous solution of Cu (II) chloride, the optimum copper (II) concentration in the analyzed sample is (0.0001M) , the size of bubbles 2.6 L\min, the shaking time is (15 min), and the pump flowrate is ( 50sec/mL). In these optimum conditions, the extraction degree was (91.1 %). The results of the innovative bubbles extraction method were compared with previous studies, and found they were more efficient than the classical methods of extraction using funnel separation and multiple extraction.

Adsorption of Biebrich Scarlet Dye into Remains Chromium and Vegetable Tanned Leather as Adsorbents

Chromium tanned leather wastes (CTLW) and vegetable tanned leather wastes (VTLW) were used as adsorbent materials to remove the Biebrich scarlet dye (BS), as an anionic dye from wastewater, using an adsorption method. The effects of various factors, such as weight of leather waste, time of shaking, and the starting concentration of Biebrich scarlet dye, temperature and pH were studied. It described the adsorption process using Langmuir and Freundlich isotherm models. The obtained results agreed well with the Langmuir model, and the maximum adsorption capacities of CTLW and VTLW were 73.5294 and 78.1250 mg.g⁻¹, respectively, suggesting a monolayer adsorption process. The adsorption kinetic was found to follow a pseudo-second-order kinetic model with correlation coefficients R2 &gt; 0.9982 and 0.9900 for CTLW and VTLW, respectively. The results predicted that chromium leather wastes were more suitable adsorbents for the removal of BS dye from wastewater than vegetable tanned leather wastes, and the adsorption process is endothermic, according to the study of the effect of temperature.

Evaluation of the efficiency of ZnCl2 activated cocoa pod husk charcoal on the removal of Cu2+, Cd2+, and Pb2+ ions from aqueous solution

The efficiency of ZnCl2-activated cocoa pod husk charcoal (ACPHC) in removing Pb(II), Cu(II) and Cd(II) ions from aqueous solution was investigated under different conditions of shaking speed, contact time, adsorbent dose, adsorbate concentration, pH, and temperature with a view to widening the applications of the husk. Adsorption equilibrium, kinetics and desorption studies were conducted. Activated carbon produced at 650 °C was found to give the best desired properties. The optimum shaking time and pH value were 45 min and 6. The shaking speed of 700 rpm gave maximum removal efficiency (mean ± sd) 97.02 ± 0.34%, 96.24 ± 0.19%, and 96.85 ± 0.01% for Pb(II), Cu(II), and Cd(II) ions at the optimum pH, 25 °C, and 0.1 g adsorbent/25 ml solution with adsorption capacities of 2.426, 2.406, and 2.421 mg/g, respectively. While the average capacity at the optimum contact time was 2.290 mg/g. Non-linear Temkin and Redlich–Peterson and linear Langmuir isotherm models gave the best description of the adsorption equilibrium of the metal ions onto ACPHC surface, while pseudo-second order kinetics model gave the best description of the adsorption kinetics. The rate of removal of the metal ions was in the order Pb(II) > Cu(II) > Cd(II). The regeneration of the spent adsorbent was efficient with respect to the considered metal ions. The recovery values were 96.72 ± 0.43%, 92.76 ± 0.49%, and 91.66 ± 0.34% for Pb(II), Cu(II), and Cd(II) ions, respectively. Thus ACPHC was found to be an efficient low-cost material for the removal of the studied metal ions from aqueous solution.

Nitric Acid as a Cold Extractor of Total Nutrient Contents from Mineral Fertilizers

ABSTRACT Chemical characterization of fertilizers, in terms of total nutrient content, is essential for quality control and definition of field-based rates. The Ministry of Agriculture, Livestock and Supply (MAPA) by IN/2007 recommends different methods for nutrient content extraction for fertilizers. These methods can have high analytical costs, be laborious, and generate large quantities of residues. Therefore, this work proposes a simple and more environmentally friendly extraction method by using nitric acid solution to extract total content of nutrients from fertilizers, which has the advantage of a cold extraction, less residue generation, and easier execution. The experiment was carried out using eight nutrient sources (tricalcium phosphate, monocalcium phosphate, potassium chloride, zinc oxide, copper oxide, manganese oxide, ulexite, and a mixture of soluble sources of these nutrients), four nitric acid concentrations (0.0, 1.0, 2.5, or 5.0 mol L−1), and six shaking times (10, 20, 30, 40, 50, or 60 min). A completely randomized design with three replicates was used. These data indicated 2.5 mol L−1 HNO3 as suitable concentration to extract total nutrient content from the sources. In addition, as there was no shaking time effect on elements extraction; in a second trial, we compared the performance of HNO3- at 2.5 mol L−1 under a shaking time of 60 min across MAPA methods. The results evidenced that soluble contents extracted by both methods were highly correlated, recovering equivalent amounts of B and K. For other nutrients, nitric acid method extracted a greater amount than MAPA method. Therefore, this paper represents a first approach to the use of a method based on nitric acid for the recovery of total nutrient contents (P, K, Ca Mg, S, B, Cu, Mn, and Zn) in mineral fertilizers of varying solubility.

Used central composite chemometric method to adsorption gentian violet dye by nano activated charcoal

In this paper; a modern method was used to remove the Gentian violet dye (GV) from its aqueous solutions by chemometric separation. The Nano charcoal activated (NCA) was used to remove the GV, and the factors affecting the adsorption process were studied simultaneously to reduce the number of experiments followed and to rely on a central composite design which type CCD and the method of response surface by used STATISTICA 12 program. That gives the relationship between all the variables simultaneously. It was found that, the optimum removal efficiency reached 98.042% and it was obtained under the following conditions; The initial concentration of (GV) 12.086 mg/L, Amount of Nano charcoal activated 0.371 g, pH 7.567, Shaking time 22.934 min, and Temperature 312.092 K.

Stepwise Recovery of Molybdenum, Vanadium, and Tungsten with Amino-Type “Trident” Molecule by Stripping

ABSTRACT The long-chain tripodal amino reagent 1,1,1-tris(aminomethyl)nonane was prepared and used to extract various metal species. The results were compared with the results of extractions using the related long-chain primary decylamine. The study was focused on the extraction of the oxyanions of V(IV), Mo(VI), and W(VI). Factors affecting the extraction efficiency were the shaking time, pH, and diluent. The oxyanion species distributions particularly strongly affected the oxyanion extraction efficiencies. The tripodal amino reagent extracted Mo(VI) with a good degree of specificity at pH 5–6, and the amount of Mo(VI) extracted increased until 12–14 min had passed but then decreased. The relationship between the amount of Mo(VI) extracted, the potential, and the pH suggested that a heptanuclear Mo(VI) species was extracted by the protonated tripodal amino reagent until 12–14 min had elapsed. The data further suggested that the change in pH at that point caused the heptanuclear Mo(VI) species to be converted into a mononuclear species because of protonation of the amino reagent, meaning the extracted Mo(VI) then started to be released back into the solution. The Mo(VI) extraction sequence did not include any redox reactions. From the experimental results, a stepwise method for stripping the metals from the organic phase was developed to recover molybdenum, tungsten, and vanadium. Multiple protonation of the tripodal amino reagent at different pK a values was taken into account as a “structural effect” of the tripodal compound.