One-Step Process Using CO₂ for the Preparation of Amino-Functionalized Mesoporous Silica for CO₂ Capture Application

In this study, a novel and facile one-step method using CO₂ for the preparation of amino-functionalized mesoporous silica for CO₂ capture application was introduced. 3-Aminopropyltriethoxysilane (APTES, 30 wt % in water) was first bubbled with CO₂ and then mixed with sodium silicate to produce amino-functionalized mesoporous silica. Three adsorbents, namely, precipitated silica adsorbent (PSA), silicagel adsorbent (SGA), and condense silicagel adsorbent (C-SGA), were synthesized by tuning CO₂ pressure when preparing CO₂ absorbed APTES solution and aging temperatures of obtained hydrogel, respectively. PSA has large primary particles (200–1000 nm) with 73.4 m²/g in surface area and 0.1 cm³/g in pore volume. SGA has smaller silica primary particles (10–20 nm) with higher surface area (205.9 m²/g) and higher pore volume (0.70 cm³/g). When PSA and SGA hydrogels were aged at 110 °C, they transformed to a condensed silicagel adsorbent (C-SGA) with very low surface area (12.0 m²/g) and pore volume (0.05 cm³/g). The existence of amino-functional groups in the adsorbents was confirmed by Fourier transform infrared spectroscopy technique and energy dispersive spectroscopy coupled with a scanning electron microscope. PSA had the highest CO₂ loading with 45.1 mg/g at the adsorption temperature of 50 °C, and CO₂ loading decreased with the increase in adsorption temperature. This adsorbent has low CO₂ adsorption heat (66 kJ/mol) and heat capacity (1.25 kJ/kg °C) and is thermally stable, indicating that it could be suitable for CO₂ capture application. The success of the proposed one-step process does not only provide a facile method to synthesize solid adsorbent for CO₂ capture but also contributes an additional option to CO₂ utilization

Potential for the Simultaneous Capture and Utilization of CO2 Using Desalination Reject Brine: Amine Solvent Selection and Evaluation

AbstractIn the present study, the potential for the use of different amines with desalination brines for the simultaneous capture and conversion of CO2 into solid bicarbonates was evaluated. The focus of this work was to find the most suitable amine solvent for this proposed process. Various classes of amine solvents such as primary, secondary, tertiary and cyclic amines were identified and evaluated using the following parameters: Precipitate yield, CO2 capacity and Sodium conversion. The results showed that bicarbonate salts of good purity can be synthesized by bubbling simulated flue gas into amine/brine solution. Also the sterically hindered amine, AMP, was found to be the best amine for the process due to its high precipitate yield and sodium conversion. Sodium removal above 80% was obtained when AMP was used. For all amines tested, the precipitated bicarbonate had a purity of over 95% while the CO2 capacity varied, with Piperazine having the highest. The obtained results demonstrate that the proposed process is a promising technology for the simultaneous capture and utilization of CO2 using desalination reject brine

Hazardous and emerging contaminants removal from water by plasma-based treatment: A review of recent advances

The opportunities, challenges, and future trends of the application of non-thermal plasma (NTP) technology in water purification is critically reviewed. Different plasma methods were introduced and discussed, then we zeroed in on NTP (a direct discharge plasma) because of its low energy requirement. Recent and major strategies for the application of NTP in water treatment were then presented and discussed. The main opportunities and challenges faced in the application of NTP for water purification were analyzed and discussed. Finally, the future trend in the application of NTP in water treatment was projected, and a possible future direction of research in water treatment was proposed. While NTP has gained massive attention for water purification, there is still room for improvement in terms of leveraging its synergy with advanced water treatment technologies like catalysis, membrane filtration, and biological degradation. These findings presented herein lay the foundation for future improvements that can be implemented in the application of NTP in water treatment

Enhanced infection prophylaxis reduces mortality in severely immunosuppressed HIV-infected adults and older children initiating antiretroviral therapy in Kenya, Malawi, Uganda and Zimbabwe: the REALITY trial

Meeting abstract FRAB0101LB from 21st International AIDS Conference 18–22 July 2016, Durban, South Africa. Introduction: Mortality from infections is high in the first 6 months of antiretroviral therapy (ART) among HIV‐infected adults and children with advanced disease in sub‐Saharan Africa. Whether an enhanced package of infection prophylaxis at ART initiation would reduce mortality is unknown. Methods: The REALITY 2×2×2 factorial open‐label trial (ISRCTN43622374) randomized ART‐naïve HIV‐infected adults and children >5 years with CD4 <100 cells/mm3. This randomization compared initiating ART with enhanced prophylaxis (continuous cotrimoxazole plus 12 weeks isoniazid/pyridoxine (anti‐tuberculosis) and fluconazole (anti‐cryptococcal/candida), 5 days azithromycin (anti‐bacterial/protozoal) and single‐dose albendazole (anti‐helminth)), versus standard‐of‐care cotrimoxazole. Isoniazid/pyridoxine/cotrimoxazole was formulated as a scored fixed‐dose combination. Two other randomizations investigated 12‐week adjunctive raltegravir or supplementary food. The primary endpoint was 24‐week mortality. Results: 1805 eligible adults (n = 1733; 96.0%) and children/adolescents (n = 72; 4.0%) (median 36 years; 53.2% male) were randomized to enhanced (n = 906) or standard prophylaxis (n = 899) and followed for 48 weeks (3.8% loss‐to‐follow‐up). Median baseline CD4 was 36 cells/mm3 (IQR: 16–62) but 47.3% were WHO Stage 1/2. 80 (8.9%) enhanced versus 108(12.2%) standard prophylaxis died before 24 weeks (adjusted hazard ratio (aHR) = 0.73 (95% CI: 0.54–0.97) p = 0.03; Figure 1) and 98(11.0%) versus 127(14.4%) respectively died before 48 weeks (aHR = 0.75 (0.58–0.98) p = 0.04), with no evidence of interaction with the two other randomizations (p > 0.8). Enhanced prophylaxis significantly reduced incidence of tuberculosis (p = 0.02), cryptococcal disease (p = 0.01), oral/oesophageal candidiasis (p = 0.02), deaths of unknown cause (p = 0.02) and (marginally) hospitalisations (p = 0.06) but not presumed severe bacterial infections (p = 0.38). Serious and grade 4 adverse events were marginally less common with enhanced prophylaxis (p = 0.06). CD4 increases and VL suppression were similar between groups (p > 0.2). Conclusions: Enhanced infection prophylaxis at ART initiation reduces early mortality by 25% among HIV‐infected adults and children with advanced disease. The pill burden did not adversely affect VL suppression. Policy makers should consider adopting and implementing this low‐cost broad infection prevention package which could save 3.3 lives for every 100 individuals treated