Hydrothermal liquefaction is a technique for obtaining clean biofuel from biomass in the presence of a solvent at moderate to high temperature (250–550 °C) and pressure (5–25 MPa). Hydrothermal decomposition of biomass leads to the formation of various compounds depending upon operating parameters. The role of processing conditions including final liquefaction temperature, residence times, rate of biomass heating, size of biomass particles, type of solvent media and hydrogen donor solvents is important for the bio-oil yield and quality of the product. The effect of these parameters on the yield and composition of the liquid products is reviewed in the paper. A brief description about the decomposition mechanism is also included to highlight the product types during hydrothermal liquefaction.

A review on process conditions for optimum bio-oil yield in hydrothermal liquefaction of biomass

Recent progress in the direct liquefaction of typical biomass

Thermochemical liquefaction characteristics of microalgae in sub- and supercritical ethanol

Direct liquefaction of Dunaliella tertiolecta for bio-oil in sub/supercritical ethanol-water.

Comparative studies of thermochemical liquefaction characteristics of microalgae using different organic solvents

Liquefaction of rice straw in sub- and supercritical 1,4-dioxane–water mixture

Sulfate radical (SO4•-) based advanced oxidation processes (SR-AOPs) is a very important chemical oxidation technology for the degradation of recalcitrant organic pollutants in water and has been well developed. Recently, transition metals or their oxides-modified biochar has been widely used as the catalyst to catalyze peroxymonosulfate (PMS) and peroxydisulfate (PS) in SR-AOPs due to their outstanding properties (e.g., large surface area, high stability, abound catalytic sites, and diversity of material design, etc.). These composite materials not only combine the respective beneficial characteristics of biochar and transition metals (or their oxides) but also often present synergistic effects between the components. In this review, we present the synthesis of different types of transition metal (or metal oxides)/biochar-based catalysts and their application in SR-AOPs. The catalytic mechanism, including the generation process of free radicals and other reaction pathways on the surface of the catalyst were also carefully discussed. Particular attention has been paid to the synergistic effects between the components that result in enhanced catalytic performance. At the end of this review, the future development prospects of this technology are proposed. 

The application of transition metal-modified biochar in sulfate radical based advanced oxidation processes.

Metal-organic frameworks template-directed growth of layered double hydroxides: A fantastic conversion of functional materials

Multiple optimization strategies for improving photocatalytic performance of the h-BN/flower-ring g-C3N4 heterostructures: Morphology engineering and internal electric field effect

Recent advances in metal–organic framework-based materials for removal of fluoride in water: Performance, mechanism, and potential practical application

Mingyang Cheng

Papers

Liquefaction of rice straw in sub- and supercritical 1,4-dioxane–water mixture

The application of transition metal-modified biochar in sulfate radical based advanced oxidation processes.

Metal-organic frameworks template-directed growth of layered double hydroxides: A fantastic conversion of functional materials

Multiple optimization strategies for improving photocatalytic performance of the h-BN/flower-ring g-C3N4 heterostructures: Morphology engineering and internal electric field effect

Recent advances in metal–organic framework-based materials for removal of fluoride in water: Performance, mechanism, and potential practical application