Sonodegradation of amitriptyline and ibuprofen in the presence of Ti3C2Tx MXene

This study, which investigated the sonodegradation of selected pharmaceutical active compounds (PhACs) (amitriptyline (AMT) and ibuprofen (IBP)) with MXene, was carried out in an aqueous solution. To investigate the practicality of the degradation process, the experiments were conducted in various water quality conditions, including pH, temperature, natural organic matter, and ionic strength. Based on the experimental results, the produced hydrogen peroxide, which could be a representative of the produced OH radicals, was a vital factor that affected the degradation performance of both PhACs. To confirm the importance of OH radicals, the effect of a OH radical promoter (H2O2) and scavenger (t-BuOH) was also studied. In addition, the synergism between ultrasonication (US) and MXene was evaluated with the rate constants of US only, MXene only, and a US/MXene combined system. Mineralization of the PhACs was also investigated, and removal of AMT was higher than that of IBP, which could be attributed to the physicochemical properties of the compounds and enhanced adsorption by the well-dispersed MXene. Overall, utilization of MXene by means of ultrasonication could enhance the removal performance of PhACs in water

Magnesium silicate impregnation on palm-shell activated carbon powder for enhanced heavy metal adsorption / Choong Choe Earn

In this work, palm-shell waste powder activated carbon (PPAC) coated by magnesium silicate (PPAC-MS) were successfully synthesized by the impregnation of magnesium silicate (MgSiO3) using economical material (silicon dioxide powder) via mild hydrothermal approach under one-pot synthesis for the first time. Surprisingly, PPACMS exhibited a homogeneous thin plate mesh-like structure, as well as meso- and macro-pores with a high surface area of 772.1 m2 g-1. Different impregnation ratios of MgSiO3 onto PPAC were tested from 0% to 300%. High amounts of MgSiO3 led to high Cu (II) adsorption capacity. A ratio of 1:1, designated as PPAC-MS 100, was considered optimum because of its chemical stability in solution. The maximum adsorption capacity of PPAC-MS 100 for Cu (II) obtained by isotherm experiments was 369 mg g-1. Kinetic adsorption data fitted to pseudo-second-order revealed chemisorption. Increasing ionic strength reduced Cu (II) adsorption capacity because of the competition effect between Na+ and Cu2+. Three times of regeneration studies were also conducted for Cu (II) removal. In addition, PPAC-MS 100 showed sufficient adsorption capacity on removal Zn (II), Al (III), Fe (II), Mn (II), and As (V) with the adsorption capacity of 373 mg g-1, 244 mg g-1, 234 mg g-1, 562 mg g-1, 191 mg g-1, respectively. As an effective adsorbent, PPAC-MS 100 simultaneously removes Bisphenol A (BPA) and Pb (II) in single and binary mode. Due to its specific morphological characteristics, PPAC-MS 100 had adsorption capacities of Pb (II) as high as 419.9 mg g-1 and 408.8 mg g-1 in single mode and binary mode based on Freudliuch isotherm model while those for BPA by PPAC-MS were 168.4 mg g-1 and 254.7 mg g-1 for single mode and binary modes corresponding to Langmuir isotherm model. Experiment results also indicated that the synergistic removal of BPA occurred because the precipitation process of Pb (II) leads to the co-precipitation of BPA with Pb(OH)2 compound. PPAC-MS showed a good reusability for 5 regeneration cycles using Mg (II) solution followed by thermal treatment. PPAC-MS is characterized by Fourier Transformed Infrareds (FTIR), nitrogen adsorption/desorption analysis, X-Ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Field Emission Scanning Electron Microscope (FESEM). Overall, PPAC-MS has a high potential in the treatment process for wastewater containing both toxic heavy metals and emerging pollutants due to its high sorption capacities and reusability, while remaining economical through the reuse of palm-shell waste materials

One Step Hydrothermal Synthesis of Magnesium Silicate Impregnated Palm Shell Waste Activated Carbon for Copper Ion Removal

Magnesium silicate impregnated onto palm-shell waste activated carbon (PPAC) underwent mild hydrothermal treatment under one-pot synthesis, designated as PPAC-MC. Various impregnation ratios from 25 to 300% of MgSiO3 onto PPAC were tested. High levels of MgSiO3 led to high Cu(II) adsorption capacity. A ratio of 1:1 (PPAC-MS 100) was considered optimum because of its chemical stability in solution. The maximum adsorption capacity of PPAC-MS 100 for Cu(II) obtained by isotherm experiments was 369 mg g−1. The kinetic adsorption data fitted to pseudo-second-order model revealed as chemisorption. Increasing ionic strength reduced Cu(II) adsorption capacity due to the competition effect between Na+ and Cu2+. In addition, PPAC-MS 100 showed sufficient adsorption capacity for the removal of Zn(II), Al(III), Fe(II), Mn(II), and As(V), with adsorption capacities of 373 mg g−1, 244 mg g−1, 234 mg g−1, 562 mg g−1, 191 mg g−1, respectively. Three regeneration studies were also conducted. PPAC-MS was characterized using Fourier Transformed Infrared (FTIR), X-Ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Field Emission Scanning Electron Microscope (FESEM). Overall, PPAC-MS 100 is a competitive adsorbent due to its high sorption capacity and sufficient regeneration rate, while remaining economical through the reuse of palm-shell waste materials

Nitrate Capture Investigation in Plasma-Activated Water and Its Antifungal Effect on Cryptococcus pseudolongus Cells

This research investigated the capture of nitrate by magnesium ions in plasma-activated water (PAW) and its antifungal effect on the cell viability of the newly emerged mushroom pathogen Cryptococcus pseudolongus. Optical emission spectra of the plasma jet exhibited several emission bands attributable to plasma-generated reactive oxygen and nitrogen species. The plasma was injected directly into deionized water (DW) with and without an immersed magnesium block. Plasma treatment of DW produced acidic PAW. However, plasma-activated magnesium water (PA-Mg-W) tended to be neutralized due to the reduction in plasma-generated hydrogen ions by electrons released from the zero-valent magnesium. Optical absorption and Raman spectra confirmed that nitrate ions were the dominant reactive species in the PAW and PA-Mg-W. Nitrate had a concentration-dependent antifungal effect on the tested fungal cells. We observed that the free nitrate content could be controlled to be lower in the PA-Mg-W than in the PAW due to the formation of nitrate salts by the magnesium ions. Although both the PAW and PA-Mg-W had antifungal effects on C. pseudolongus, their effectiveness differed, with cell viability higher in the PA-Mg-W than in the PAW. This study demonstrates that the antifungal effect of PAW could be manipulated using nitrate capture. The wide use of plasma therapy for problematic fungus control is challenging because fungi have rigid cell wall structures in different fungal groups

Highly Exposed -NH2 Edge on Fragmented g-C3N4 Framework with Integrated Molybdenum Atoms for Catalytic CO2 Cycloaddition: DFT and Techno-Economic Assessment

This study focuses on the applicability of single-atom Mo-doped graphitic carbon nitride (GCN) nanosheets which are specifically engineered with high surface area (exfoliated GCN), -NH2 rich edges, and maximum utilization of isolated atomic Mo for propylene carbonate (PC) production through CO2 cycloaddition of propylene oxide (PO). Various operational parameters are optimized, for example, temperature (130 degrees C), pressure (20 bar), catalyst (Mo(2)GCN), and catalyst mass (0.1 g). Under optimal conditions, 2% Mo-doped GCN (Mo(2)GCN) has the highest catalytic performance, especially the turnover frequency (TOF) obtained, 36.4 h(-1) is higher than most reported studies. DFT simulations prove the catalytic performance of Mo(2)GCN significantly decreases the activation energy barrier for PO ring-opening from 50-60 to 4.903 kcal mol(-1). Coexistence of Lewis acid/base group improves the CO2 cycloaddition performance by the formation of coordination bond between electron-deficient Mo atom with O atom of PO, while -NH2 surface group disrupts the stability of CO2 bond by donating electrons into its low-level empty orbital. Steady-state process simulation of the industrial-scale consumes 4.4 ton h(-1) of CO2 with PC production of 10.2 ton h(-1). Techno-economic assessment profit from Mo(2)GCN is estimated to be 60.39 million USD year(-1) at a catalyst loss rate of 0.01 wt% h(-1)