Kinetics and Thermodynamic Studies for Removal of Trypan Blue and Methylene Blue from Water Using Nano Clay Filled Composite of HTAB and PEG and its Antibacterial Activity

This work describes the preparation of new eco-friendly adsorbents with a simple method. At first, Montmorillonite (MMT) was modified with surfactant HTAB (MMT@HTAB) and then with polymer PEG (MMT@HTAB@PEG). The as-synthesized materials were characterized by several characterization techniques, including XRD, FTIR, SEM, TEM, TGA, N2 adsorption/desorption isotherm analysis by the BET method and zeta potential measurement then evaluated as adsorbents for removal of both methylene blue (MB) as a cationic dye and trypan blue (TB) as the anionic dye from aqueous solution under different contact time, dye concentration, temperature, and pH. The obtained results confirm the intercalation of surfactant within the clay layers, while the obtained nanocomposite showed different morphologies and structures in which the exfoliated and intercalated forms were obtained. The maximum adsorption capacity of TB and MB was found to be 190.81 and 237.22 mg/g, respectively, with MMT@HTAB@PEG adsorbent in an initial concentration of 100 mg/L at alkaline pH in 35 min and a temperature of 25 °C. The adsorption kinetics of TB and MB on MMT@HTAB@PEG was best fitted by the pseudo-second order model, and the isotherms results reveals better consistency of the Langmuir model, indicating that the adsorption is favorable and in the form of multilayers. The thermodynamic study showed that the adsorption processes of TB and MB by the both MMT@HTAB and MMT@HTAB@PEG adsorbents occur in an autonomous way and the temperature has not a significant effect on the adsorption capacity of TB and MB dyes. In addition, MMT@HTAB showed good antibacterial activity against both Escherichia coli (ATCC 8739) and Micrococcus luteus (ATCC 9341) bacteria compared to MMT@HTAB@PEG. The broadcast area was found to be 6 and 5 mm in Escherichia coli (ATCC 8739) and Micrococcus luteus (ATCC 9341), respectively

Synthesis and Characterization of Amphiphilic Diblock Copolymer by Reverse Iodine Transfer Polymerization (RITP)

Iodine transfer radical homo- and diblock copolymerization of N-[3-(dimethylamino)propyl] methacrylamide (DMAPMA) with methyl methacrylate (MMA) were carried out in the presence of iodine I2 and 2,2′-azobis(isobutyronitrile) (AIBN) as chain transfer agent and initiator, respectively. Using reverse iodine transfer polymerization (RITP) method based on the in situ generation of transfer agents using molecular iodine I2. The homopolymer and copolymer were characterized by FT-IR and 1H NMR. The self-assembly behaviours of diblock copolymer in water are studied by viscosity and tensiometry techniques. The water-soluble fraction of P(DMAPMA-b-MMA) block copolymer formed micelles which were investigated at 25°C in water at 0.2 mg.mL−1 concentration using a tensiometry device. Dynamic light scattering technique (DLS) was performed over a wide range of concentration to determine hydrodynamic size of the aggregates

Removal of crystal violet dye using a three-dimensional network of date pits powder/sodium alginate hydrogel beads: Experimental optimization and DFT calculation

Biodegradable and very low-cost adsorbent beads were prepared from date pits powder (DP) and sodium alginate (SA). DP to SA ratios was varied (1/2; 1/4 and 1/6) and used to eliminate Crystal violet (CV) a cationic dye. Adsorbents were characterized by FTIR, SEM-EDS, UV–vis DR, TGA and the point of zero charge (pHPZC). The optimal composite beads SA@6DP show high adsorption capacities of 83.565 mg/g toward CV than SA@2DP and SA@4DP. The kinetics investigation showed that the adsorption is well described by the pseudo-second-order kinetic (R2 = 0.998). The thermodynamics and isotherms studies exhibit that the adsorption phenomenon for SA@6DP adsorbent is endothermic and significantly fitted with the Redlich-Peterson model. The experimental adsorption tests were optimized by the Box-Behnken design (BBD) which led to conclude the maximal CV removal obtained by SA@6DP was 99.873 % using [CV] = 50 mg/L, adsorbent mass = 20 mg and 48 h of contact time. The theoretical calculation proved that the CV molecules favor the mode of attack due to their electrophilic character and can accept the SA@6DP adsorbent electrons more easily to form an anti-bonding orbital. SA@6DP hydrogel beads are therefore an exceptional bio-adsorbent that offers excellent adsorption performance

Green Synthesis of Silver Nanoparticles Using Aqueous <i>Citrus limon</i> Zest Extract: Characterization and Evaluation of Their Antioxidant and Antimicrobial Properties

The current work concentrated on the green synthesis of silver nanoparticles (AgNPs) through the use of aqueous Citruslimon zest extract, optimizing the different experimental factors required for the formation and stability of AgNPs. The preparation of nanoparticles was confirmed by the observation of the color change of the mixture of silver nitrate, after the addition of the plant extract, from yellow to a reddish-brown colloidal suspension and was established by detecting the surface plasmon resonance band at 535.5 nm, utilizing UV-Visible analysis. The optimum conditions were found to be 1 mM of silver nitrate concentration, a 1:9 ratio extract of the mixture, and a 4 h incubation period. Fourier transform infrared spectroscopy spectrum indicated that the phytochemicals compounds present in Citrus limon zest extract had a fundamental effect on the production of AgNPs as a bio-reducing agent. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential (ZP), dynamic light scattering (DLS), SEM, EDX, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis, which showed crystalline spherical silver nanoparticles. In addition, the antimicrobial and antioxidant properties of this bioactive silver nanoparticle were also investigated. The AgNPs showed excellent antibacterial activity against one Gram-negative pathogens bacteria, Escherichia coli, and one Gram-positive bacteria, Staphylococcus aureus, as well as antifungal activity against Candida albicans. The obtained results indicate that the antioxidant activity of this nanoparticle is significant. This bioactive silver nanoparticle can be used in biomedical and pharmacological fields