Torrefaction of organic municipal solid waste to high calorific value solid fuel using batch reactor with helical screw induced rotation.

The potential of producing high calorific value (CV) solid fuel was investigated in a helical screw rotation-induced (HSRI) fluidized bed reactor based on mechanical fluidization. The study revealed that the HSRI torrefaction improved the torrefied product properties. For the 40 and 0 rpm conditions, the CV, fixed carbon, and ash contents of torrefied solid fuel increased with an increase in temperature. In contrast, volatile matter, moisture content, mass and energy yields decreased. The CV of torrefied solid fuel increased by a factor of 1.43 and 1.58 at 280 °C for the 40 and 0 rpm conditions, respectively. HSRI torrefaction enhanced the removal of hydroxyl functional group. HSRI torrefaction improved the hydrophobicity of the torrefied solid fuel. Therefore, the HSRI fluidized bed reactor promotes uniform temperature distribution, a higher heat transfer rate within the sample particles in the reactor, and a homogenous torrefied solid product compared to the fixed bed reactor.

A review on synthesis, modification method, and challenges of light-driven H2 evolution using g-C3N4-based photocatalyst.

The energy scarcity is exacerbating and needs an urgent solution. The most plausible solution to address the forthcoming energy scarcity is to diversify the energy sources. Developing the water-splitting process (WSP) efficiency depends on solar energy representing "21st-century dream technology". We present a comprehensive review of related papers employing graphitic carbon nitride (g-C3N4) as pure, doped, or composite nanostructure in the evolution of hydrogen from water dissociation under simulated sunlight irradiation, mainly in the last ten years. Herein, after a concise introduction to the main principle of the water-splitting process, the methods to synthesize, modify and upgrade the photocatalytic performance of g-C3N4 were reviewed in detail. Moreover, the main challenges of using g-C3N4-based photocatalytic material in WSP have been mentioned. The report mainly targets the g-C3N4 character, synthesis method, photocatalytic activity, and strategies toward enhancing photoreactivity under visible light, along with the reusability of the fabricated nanohybrid catalysts. Above and over, this review suggests the potential of g-C3N4 to produce green H2 from water at a competitive price, which can contribute to satisfying the global energy sector demand and suppressing global warming.

A review of microwave pyrolysis as a sustainable plastic waste management technique.

The high demand for plastic has led to plastic waste accumulation, improper disposal and environmental pollution. Even though some of this waste is recycled, most ends up in landfills or flows down rivers into the oceans. Therefore, researchers are now exploring better ways to solve the plastic waste management problem. From a socio-economic perspective, there is also a concerted effort to enable energy recovery from plastic waste and convert it into useful products to generate income for targeted segments of the population. In fact, this concept of waste-to-wealth has been adopted by the United Nations as part of its Sustainable Development Goals strategies. The current article begins by reviewing the strengths and weaknesses of plastic recycling before focusing specifically on microwave pyrolysis as an alternative to conventional technologies in plastic waste management, due to its benefit in providing fast and energy-efficient heating. The key parameters that are reviewed in this paper include different types of plastic, types of absorbent, temperatures, microwave power, residence time, and catalysts. The yield of the final product (oil, gaseous and char) varies depending on the main process parameters. Key challenges and limitations of microwave pyrolysis are also discussed in this paper.