Optimization of Ultrasound-Assisted Extraction of Polyphenol Content from Zea mays Hairs (Waste)

The aim of this study was to achieve the best extraction efficiency of the hydroethanolic extract of Zea mays hairs. The impacts of ethanol concentration, extraction time, and solvent /material ratio were studied in relation to the performance of Zea mays extracts by ultrasonic extraction at 50 kHz and room temperature. All extracts were quantitatively characterized in terms of polyphenol content. Response surface methodology (RSM) was carried out to optimize the extraction process and increase extraction efficiency. In the experiments, different concentrations of ethanol:water were used. The efficiency of the extraction process was determined from an analysis of variance (ANOVA). The maximum extraction efficiency of the hydroethanolic extraction (31.37%) and the quantitative value of the polyphenol content (257.87 mg EAG/g extract) were obtained using a treatment time of 40 min, an ethanol:water (70 : 30), and a solvent/material ratio (11 mL/g). The results obtained indicate that ultrasonic-assisted extraction is an effective method for extracting natural compounds from Zea mays, thus allowing the full use of this abundant and inexpensive industrial waste

Zn–Al layered double hydroxides intercalated with carbonate, nitrate, chloride and sulphate ions: Synthesis, characterisation and dye removal properties

In this work, Zn–Al layered double hydroxides intercalated with carbonate, nitrate, chloride and sulphate ions were synthesised via a co-precipitation method at a constant solution pH. The as-synthesised samples were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and simultaneous thermogravimetric/differential thermal analysis (TGA-DTA). The XRD patterns showed that Zn-Al-SO4 had the greatest interlayer spacing, followed by Zn-Al-Cl, Zn-Al-NO3 and Zn-Al-CO3. The FTIR spectra clearly confirmed the presence of intercalated anions in the structure of the LDHs. Batch experiments for methyl orange (MO) adsorption onto synthesised samples were investigated under various conditions such as contact time, initial dye concentration and solution pH. The experimental results show that pH is the most influencing factor. The effective pH range for the MO removal was found to be 3.5–4.5. The kinetics data can be described accurately by a pseudo-second-order kinetic model instead of a pseudo-first-order model. The equilibrium data were analysed using the Langmuir, Freundlich and Dubinin–Radushkevich models. The results showed that the Langmuir and Dubinin–Radushkevich isotherm models fit well to the experimental data. The Zn-Al-LDH samples exhibited exceptional Langmuir maximum adsorption capacities of 2758, 2455, 2270 and 1684 mg/g for Zn-Al-SO4, Zn-Al-Cl, Zn-Al-NO3 and Zn-Al-CO3, respectively

Phytochemical Screening, Polyphenols Content, Antioxidant Power, and Antibacterial Activity of Herniaria hirsuta from Morocco

The aim of this study is to investigate in vitro antioxidant and antibacterial activities of the aqueous and hydroethanolic extracts for aerial parts of Herniaria hirsuta. Extracts were screened for their possible antioxidant activities by three tests: DPPH free radical-scavenging, reducing power, and molybdenum systems. The screening of antibacterial activity of extracts was individually evaluated against sixteen bacteria species using a disc diffusion method. Flavonoids, total phenols, and tannins content were performed for both extracts. It shows higher content in the hydroethanolic extract. The hydroethanolic extract showed a significant antioxidant activity for the three methods studies to the aqueous extract, but nonsignificant results compared to the reference (BHT). However, both extracts have negative effect on the strains studies for the antibacterial activity

Synergetic Effect between Phenolic Extracts of Ammi visnaga and Zea mays Formulation on the Corrosion of Mild Steel in 1 M HCl Solution

The synergetic effects between hydroethanolic extracts of A. visnaga HE (AV) and Z. mays hairs HE (ZM) on corrosion of mild steel in 1 M HCl solution was investigated at 298 K by two techniques: potentiodynamic polarization (PP) methods (Tafel and Stern & Geary) and electrochemical impedance spectroscopy (EIS). The mixture of HE (AV)/HE (ZM) acted as an efficient corrosion inhibitor and its inhibition efficiency increased with concentration up to 96.55% at 0.01 gL−1 HE (AV)/0.2 gL−1 HE (ZM). The polarization curves revealed that the mixture acted as a mixed-type inhibitor, with anodic predominant action. The EIS studies were fitted by the (Rs + CPEdl)/(Rct + CPEf/Rf) equivalent circuit model. The kinetic parameters were in favor of a physisorption character of adsorption of HE (AV)/HE (ZM) components onto the mild steel surface. The influence of exposure time on the efficiency of mixture extract was investigated. Scanning electron microscopy (SEM/EDX) analyses confirmed the formation of a protective adsorbed film upon the mild steel surface

Performance of Zn-, Mg- and Ni-Al layered double hydroxides in treating an industrial textile wastewater

In this study, Zn-Al, Mg-Al and Ni-Al layered double hydroxides were successfully synthesized via co-precipitation method. Samples were characterized by XRD, FTIR, TGA-DTA, TEM and pHPZC analysis. XRD patterns showed a basal spacing increase in the order of Zn-AlNO3 (8.85Å)> Mg-AlNO3 (7.95Å)> Ni-AlNO3 (7.82Å). TEM images indicated that the Zn-AlNO3 presents circular to shaped particles with an average particle size of approximately 30 to 40 nm. Small plates assigned to sheets with hexagonal form were observed in the case of Mg-AlNO3.Ni-AlNO3 display nanostructured sphere in diameter between 5 and 10 nm. The materials were used for the removal of methyl orange (MO), as a model dye and for the treatment of a real effluent generated by a textile factory. Maximum adsorption was occurred in acidic pH solution. Kinetic data were tested using pseudo-first-order, pseudo-second-order kinetic and intra-particle diffusion models. The best fit was obtained with the pseudo-second-order kinetic model. Equilibrium data were correlated to Langmuir, Freundlich, Sips and Redlich–Peterson isotherm models. The best conditions for color and COD removal from the textile effluent sample were obtained at lower values of pH. Reduction of COD to limits authorized by Moroccan standards was obtained with 0.5g/L of LDH dosage

Color and organic matter removal from textile effluents by synthetic layered double hydroxides and natural clays

This study focused on the removal of dyes and the reduction of COD of textile effluents by natural clay and a synthesized layered double hydroxide (HDL). The raw clay used in this work was collected from the region of Safi in Morocco. Mg/Fe-LDH adsorbent was synthesized using co-precipitation method at room temperature. Samples were characterized by XRD, SEM. The different physical and chemical parameters of the textile discharges (Electrical conductivity, TSS, COD, BOD5, NO2 and Total phosphorus) were evaluated. Experimental results showed that the maximum color and COD removal depends on the adsorbent dose and solution pH

Effects of molar ratio and calcination temperature on the adsorption performance of Zn/Al layered double hydroxide nanoparticles in the removal of pharmaceutical pollutants

This work focuses on the development of zinc/aluminum layered double hydroxides (LDHs) phases intercalated by carbonates ions (Zn-Al-CO3) and their use in the removal of pharmaceutical pollutants. The materials were synthesized by the co-precipitation method at different Zn/Al molar ratios (r = 1, 3 and 5). Each synthesized material was calcined at 300, 400, 500 and 600 °C to increase their performance. Samples were characterized by various physicochemical techniques including XRD, FTIR, ICP-AES and TEM-EDX. The as-synthesized and calcined products were used for the removal of salicylic acid (SA) as a model of pharmaceutical pollutants. The results obtained show that the Zn/Al molar ratios and calcination temperatures have a great influence on the adsorption capacity. The optimum adsorption efficiency was found to be 94.59% for Zn/Al molar ratio of 3 and a calcination temperature of 300 °C. Kinetics of the adsorption takes place in two steps; the first fast rapid step can be interpreted by the adsorption on the external surface of the crystallites, while the second slow step could be due the reconstruction phenomenon of LDHs structure “memory effect”. After the adsorption processes, XRD patterns show that the calcined product (r = 3, T = 300 °C) was reconstructed by a salicylic acid. The adsorption performance was slightly decreased with regeneration cycles. Keywords: Layered double hydroxides, Reconstruction, Pharmaceutical pollutants, Regeneration, Wastewater treatmen

Adsorption behavior of methylene blue onto powdered Ziziphus lotus fruit peels and Avocado kernels seeds

In this research, two agroforestry by-products were used as adsorbents for the removal of methylene blue (MB), as a model dye, from aqueous solution. The Ziziphus lotus fruit peels (ZLP) and Avocado kernel seed (AKS) were dried and powdered to particles of sizes <125 μm. Adsorption study was carried out in batch mode under different condition by varying initial dye concentration, contact time, initial solution pH, adsorbent dosage and reaction temperature. Rate constants of the adsorption were calculated by kinetic measurements. Equilibrium data were correlated to Langmuir and Freundlich isotherm models. The best fit was obtained by Langmuir model with maximum monolayer adsorption capacities of 66.04 mg/g in the case of ZLP and 59.07 mg/g in the case of AKS. The surface properties of the adsorbents were characterized by FTIR spectroscopy, SEM-EDX analysis and the point of zero charge

Ni/Fe and Mg/Fe layered double hydroxides and their calcined derivatives: preparation, characterization and application on textile dyes removal

In this study, Mg/Fe and Ni/Fe layered double hydroxides (LDHs) with molar ratio (M2+/Fe3+) of 3 and intercalated with carbonate ions were synthesized by co-precipitation method. The as-synthesized materials and their calcined products (CLDHs) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analyses (TGA–DTA), transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (TEM-EDX), inductively coupled plasma (ICP) and elemental chemical analysis CHNSO. The materials were used as adsorbents for the removal availability of textile dyes from aqueous solution. Methylene blue (MB) and malachite green (MG), representative of cationic dyes, and methyl orange (MO) representative of anionic dyes were used as model molecules. Adsorption experiments were carried out under different parameters such as contact time, temperature, initial dyes concentration and solution pH. Experimental results indicate that CLDHs had much higher adsorption capacities compared to LDHs. Adsorption kinetic data fitted well the pseudo-second order kinetic model. The process was spontaneous, endothermic for cationic dyes and exothermic for the anionic dye. Equilibrium sorption data fitted the Langmuir model instead of Freundlich model