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In this study, two-step simple method was employed to synthesize new oligomers with significant antibacterial activity. The interaction of ethylenediamine with epichlorohydrin produced ethylenediamine-epichlorohydrin oligomer (EEO), which is subsequently modified by 2,4,5-trichlorophenol to generate ethylenediamine-epichlorohydrin-trichlorophenol oligomer (EETO). Infrared spectroscopy, nuclear magnetic resonance spectroscopy, scanning electron microscopy, and thermogravimetric analyses were used to characterize the oligomers. The amine group and C –Cl peak in the EEO and EETO spectra were both validated by the characterization data, respectively. EEO showed substantial antibacterial activity against S. aureus (1 × 107, 1 × 105, and 1 × 103 CFU/mL) with a minimal inhibition concentration (MIC) of 1250 g/mL at all concentrations. With the same concentrations, EETO demonstrated 156, 39, and 9.77 g/mL, respectively. Furthermore, in a well diffusion assay with the same microorganisms, EEO and EETO had diameters of 20 and 30 mm. Furthermore, stem cells were used to conduct a cytotoxicity test on EETO, which revealed that the compound is harmless to cells up to 10 g/mL. Both oligomers are promising antibacterial materials for liquid toilet cleaners or hospital disinfectants due to their water-soluble nature. [ABSTRACT FROM AUTHOR]

Here, trichlorovinylsilane-modified-chitosan (TVS-m-CS) film is synthesized and explicated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and X-ray diffraction (XRD). The SEM micrograph of TVS-m-CS revealed smooth structure with bulge surface. The TVS-m-CS antibacterial activity was evaluated using the broth dilution and agar diffusion methods. Results herein indicated that the TVS-m-CS exhibited enhanced water solubility (67 mg/mL) compared to the cross-linked chitosan (CS) film (5.5 mg/mL). Notably, TVS-m-CS showed a significantly enhanced antibacterial activity against E. coli, S. aureus, E. faecalis, Kleb spp. and methicillin-resistant Staphylococcus aureus (minimum inhibitory concentration [MIC] = 0.078–0.156 mg/mL and minimum bactericidal concentration [MBC] = 12.5–3.12 mg/mL) than the original CS film. Unlike most quaternized chitosan derivatives, the TVS-m-CS was prepared via an easy and simple route and exhibited a comparatively high antibacterial performance. The time-kill study revealed that 5 mg/mL TVS-m-CS exposed to the bacteria cells is sufficient to give a ~ 0.08 log10 reduction (> 99.9% kill rate) within 24 h. [ABSTRACT FROM AUTHOR]

Here, a simple yet efficient and economic strategy were demonstrated for the production of multiporous boric acid-doped sucrose carbon (Bx–pC) for supercapacitor application. The electrochemical performance was established through cyclic voltammetry and galvanostatic charge/discharge tests. Bx–pC samples were characterized by X-ray diffraction, scanning electron microscope, Raman spectroscopy and nitrogen adsorption/desorption at − 196 °C. The results reveal that the optimum boron dopant is 2 at.%; and B2–pC containing 2 at.% boron exhibited honeycomb-like porous structure (2.88 nm) and a high specific surface area of 1298.9 m2 g−1. The B2–pC-based symmetric supercapacitor delivered a remarkable energy density of ~ 56 Wh kg−1, a high power density of 1300 W kg−1 and superior capacitance of 239 F g−1 at 1 A g−1 in 1 M H2SO4 electrolyte. To establish the complex relationships between the electrode structure, active operating conditions and electrochemical performance of the supercapacitor, an artificial neural network (ANN) methodology was utilized herein. After several random runs, the ANN maintained satisfactory predictive performance with an average error rate of ~ 1.06% and desirability function of 0.93 which is closer to 1.0. [ABSTRACT FROM AUTHOR]

Zeolite was added at different weight percentages as a promoter to 10% Ni/Al2O3 and tested under atmospheric pressure for CO2 methanation for the first time. The influence of operational conditions and stability of the catalysts were investigated. The highest CO2 conversion of 99% and CH4 selectivity of 56% were achieved with 2% zeolite added catalyst at 350 °C reaction temperature. The textural and morphological characteristics of the non-promoted and zeolite promoted catalysts were established with Scanning electron microscopy, Fourier transform infrared spectrophotometer, BET analyser and X-Ray diffractometer. The addition of 2% zeolite increased the specific surface area of the catalyst while sustaining similar Ni metal surface area to the non-promoted one. However, at higher zeolite content, the CH4 selectivity reduced considerably due to the reduced Ni dispersion and specific surface area. The calcination temperature of 400 °C, H2/CO2 ratio of 4, GHSV of 72,000 SmL(gcat h)−1 resulted in the highest CH4 selectivity. The 2% zeolite added catalyst demonstrated superior resistance to deactivation in comparison to the non-promoted catalyst showing potential as a low-cost catalyst for further optimization studies. [ABSTRACT FROM AUTHOR]

The use of banana peel as a sustainable and low-cost precursor for the fabrication of effective biochar was exploited. Here, calcined magnetic biochar (CMB) was fabricated and characterized. CMB possesses surface acidic functional groups (–OH and COO−), porous structures, high saturation magnetization (39.55 emu/g), and larger surface area than the non-magnetic biochar (CB). The CMB adsorption performance (72.8, 75.9, and 83.4 mg/g for Zn2+, Cu2+, and Hg2+, respectively at pH 6) in a single component was described suitably by pseudo-second order kinetic model, Langmuir, and Redlich-Peterson adsorption isotherms. Notably, the selectivity factor values in the extended Langmuir isotherm indicated that CMB has higher adsorption affinity toward Hg2+ than Cu2+ and Zn2+ in the multi-component system. Owing to its high adsorption efficiency and fast and easy separation, the calcined magnetic biochar is considered promising and effective for the purification of heavy metal–bearing wastewater. [ABSTRACT FROM AUTHOR]

Here, a novel resorcinol–melamine–formaldehyde based mesoporous magnetic resin (m-RMF) was prepared via simple steps. The m-RMF resin was characterized by Fourier Transfer Infrared, scanning electronic microscopy and vibrating sample magnetometer. The m-RMF possesses a specific surface area of 520 m2/g, a pore volume of 0.45 cm3/g and an average pore diameter of 8.6 nm. The adsorptive performance of the m-RMF was investigated for phenol and 4-chlorophenol removal from simulated aqueous solutions under varying conditions. The results showed that m-RMF exhibited better adsorption performance for the removal of phenol (2.49 mmol/g) than 4-chlorophenol (1.5 mmol/g). The adsorption data were represented by pseudo-second order and Langmuir isotherm equations. The removal mechanism was realized by synergistic proton donor–acceptor complex, π–π interactions and hydrophobic effects. [ABSTRACT FROM AUTHOR]

Health concerns have been raised over the excessive occurrences of antibiotics such as tetracycline in aquatic environments. Adsorption is a simple and cheap technique for the removal of pharmaceuticals from industrial wastewater. To date, limited information exists on the fate, economical treatment and safe disposal of spent adsorbents in the environment, and this is often considered as the main drawback of adsorption. In this article, an alternative strategy to dispose and reuse spent inorganic adsorbents is proposed. We synthesized CoO/CuFe2O4 mixed metal oxide from layered double hydroxides by a modified co-precipitation and calcination method at 500 °C for 5 h. CoO/CuFe2O4 has a 348.5 m2/g surface area, pH point zero charge of 5.8 and an average pore diameter of 5.8 nm. Results show that the tetracycline removal efficiency at pH 6 reached 96.6% and 84-87.3% in the absence and in the presence of 4 g/L competing ions (Cl− and NO3−), respectively. Moreover, CoO/CuFe2O4 retained stable activities, of about 90%, over five consecutive recycling runs. Spent CoO/CuFe2O4 was reused as a catalyst in the presence of sunlight for degradation of azo dye, and this is the first report of achieving ~ 77% discolouration of eriochrome black T dye using a recycled adsorbent. [ABSTRACT FROM AUTHOR]