Polymer Waste Valorization into Advanced Carbon Nanomaterials for Potential Energy and Environment Applications

The rise in universal population and accompanying demands have directed toward an exponential surge in the generation of polymeric waste. The estimate predicts that world-wide plastic production will rise to ≈590 million metric tons by 2050, whereas 5000 million more tires will be routinely abandoned by 2030. Handling this waste and its detrimental consequences on the Earth's ecosystem and human health presents a significant challenge. Converting the wastes into carbon-based functional materials viz. activated carbon, graphene, and nanotubes is considered the most scientific and adaptable method. Herein, this world provides an overview of the various sources of polymeric wastes, modes of build-up, impact on the environment, and management approaches. Update on advances and novel modifications made in methodologies for converting diverse types of polymeric wastes into carbon nanomaterials over the last 5 years are given. A remarkable focus is made to comprehend the applications of polymeric waste-derived carbon nanomaterials (PWDCNMs) in the CO2 capture, removal of heavy metal ions, supercapacitor-based energy storage and water splitting with an emphasis on the correlation between PWDCNMs' properties and their performances. This review offers insights into emerging developments in the upcycling of polymeric wastes and their applications in environment and energy.

Hierarchical Porous Activated Carbon from Wheat Bran Agro-Waste: Applications in Carbon Dioxide Capture, Dye Removal, Oxygen and Hydrogen Evolution Reactions

This work reports an efficient method for facile synthesis of hierarchically porous carbon (WB-AC) utilizing wheat bran waste. Obtained carbon showed 2.47 mmol g-1 CO2 capture capacity with good CO2 /N2 selectivity and 27.35 to 29.90 kJ mol-1 isosteric heat of adsorption. Rapid removal of MO dye was observed with a capacity of ~555 mg g-1 . Moreover, WB-AC demonstrated a good OER activity with 0.35 V low overpotential at 5 mA cm-2 and a Tafel slope of 115 mV dec-1 . It also exhibited high electrocatalytic HER activity with 57 mV overpotential at 10 mA cm-2 and a Tafel slope of 82.6 mV dec-1 . The large SSA (757 m2  g-1 ) and total pore volume (0.3696 cm3  g-1 ) result from N2 activation contributing to selective CO2 uptake, high and rapid dye removal capacity and superior electrochemical activity (OER/HER), suggesting the use of WB-AC as cost effective adsorbent and metal free electrocatalyst.

Association between body mass index (BMI) and severity of coronary artery disease in young onset acute coronary syndrome (ACS)

Funding Acknowledgements

Type of funding sources: None.

Background

A high body mass index (BMI) is seems to be associated with an increased incidence of coronary artery disease. If the affected person is young, the consequences are more tragic. There are variable information on the relation of incidence and severity of coronary artery disease in high BMI populations. We have examined the association between BMI and severity of coronary artery disease in young onset Acute Coronary Syndrome (ACS).

Methods

In this prospective observational study a total number of 150 patients, aged ≤45 years presented with acute coronary syndrome were enrolled to analyze association between Body Mass Index (BMI) and severity of coronary artery disease.

Results

The mean BMI in male was 24.6±3.6 and the mean BMI in female was 25.4±3.3. Among the 150 patients, 2(1.3%) was underweight, 78(52%) was normal, 60(40%) was overweight & 10(6.7%) was obese. All underweighted patients were diagnosed as STEMI. Among the normal BMI patients, 18(23.1%) had UA, 12(15.4%) had NSTEMI & 48 (61.5%) had STEMI. Among the overweight patients, 23(38.3%) had UA, 9(15%) had NSTEMI & 28(46.7%) had STEMI. And among the obese patients, 4(40%) had UA, 1 (10%) had NSTEMI & 5(50%) had STEMI. Considering involving coronary artery, left main coronary artery involvement was 0(0%), 6 (7.7%), 5 (8.3%) & 0(0%) in underweight, normal, overweight & obese patients respectively. Left anterior descending coronary artery involvement was 2(100%), 54 (69%), 45 (75%) & 7 (70%) in underweight, normal, overweight & obese patients respectively. Left circumflex coronary artery involvement was 1(50%), 33 (42%), 25 (41.7%) & 1 (9%) in underweight, normal, overweight & obese patients respectively. And right coronary artery involvement was 1(50%), 35 (44.9%), 31 (51.7%) & 5 (50%) in underweight, normal, overweight & obese patients respectively. In underweight patients 1(50%) had SVD and 1 (50%) had TVD. In normal BMI patients 40 (51.3%) had SVD, 11(14.1%) had DVD and 19 (24.4%) had TVD. In overweight patients 27 (45%) had SVD, 15 (25%) had DVD and 13 (21.7%) had TVD. And in obese patients 5 (50%) had SVD, 3(30%) had DVD and 0 (0%) had TVD. In all BMI group SVD was more common.

Conclusion

There is no statistically significant differences in severity of coronary artery in respect to body mass index (BMI), in patients presented with acute coronary syndrome.

Estimating back to front ratio of wire screen for measurement of thoron decay products

Wire screens are widely used for measuring the fine fraction of radon/thoron decay products. Their capture efficiencies are generally defined at low aerosol concentration conditions as well as at low sampling flow rates. Effect of changes in sampling flow rate and aerosol concentration on wire screen capture efficiencies and counting correction factor has been studied in this work. Controlled experiments have been conducted using two different mesh sizes at two different aerosol concentration conditions. Experimental results were compared with the existing theories for capture efficiencies of wire screens given by Cheng and Yeh (1980) and Alonso et al. (2001); and semi empirical relation for the front to total ratio given by Solomon and Ren (1992). Theoretical predictions have been found to be relatively close to the experimental findings for moderate aerosol conditions but disagreement was observed in case of high aerosol concentration. The possible reasons for these differences have been discussed in this work.