Biochar is a carbonaceous material, which can be decorated with metals, that has been garnering attention to be used in the treatment of water due to its contribution to waste management and circular economy. This study presents the life cycle assessment (LCA) regarding the generation of Pinus patula raw biochar and its modification with iron (Fe-modified biochar). SimaPro 9.3.0.3 software was used to simulate the environmental impacts of both carbonaceous materials. The potential environmental effects obtained from the production of Pinus patula raw biochar were mainly ascribed to the source of energy utilized during this process. The potential impacts demonstrated that the generation of gases and polycyclic aromatic hydrocarbons are the main concern. In the case of Fe-modified biochar, the potential environmental effects differed only in the stage of the biomass modification with the metal. These effects are associated with the extraction of Fe and the generation of wastewater. These findings provide an insight into the environmental effects linked to the production of raw and Fe-modified biochar. However, further LCA research should be performed concerning other materials and compounds than can be generated during the biomass thermochemical conversion.

When dyes are discharged in water bodies, mutagenic, carcinogenic and teratogenic effects may be caused in both aquatic organisms and human beings. The use of biochar and the implementation of advanced oxidation processes (AOPs) are alternative treatments that have been used individually in the removal of dyes in wastewater. Besides being effective processes acting separately, biochar and AOPs can be coupled, exhibiting synergetic effects in the treatment of dyes contained in water. This work deals with the methods implemented to produce biochar from biomass, its mechanism in the removal of dyes and associated sustainability issues. Additionally, the main AOPs that have been utilized for the removal of dyes from water are covered, as well as the biochar-AOP combined processes. The future prospects for the removal of dyes from water have been also addressed. The coupling of biochar to AOPs has been proven to be more effective in the removal and mineralization of dyes than the individual treatments. In this regard and considering the scarce studies in the field, new horizons are opened on the treatment of water polluted with dyes.

The energy performance and emissions (carbon monoxide and total suspended particulate matter) of a biomass gasification-based cookstove under a modified water boiling test (WBT 4.2.3 protocol) were characterized here. The controllable process parameters analyzed were the biomass bulk density (pellets─WP and chips─WCH) and the combustion-air/gasification-air ratio (2.8, 3.0, and 3.2). Moreover, a design parameter of the cookstove was analyzed through two combustion chamber designs (combustion chambers 1 and 2). The cookstove was characterized in detail considering the complete cookstove (control volume 1), the combustion chamber (control volume 2), and the gasification process (control volume 3). The cookstove reached an average efficiency of 25.2% for pellets and 24.1% for chips. The best behavior for the cookstove was achieved when pellets were used, which is attributed to their higher bulk density and to the fact that during their gasification process, the biochar yield was 12% higher, while the biomass consumption decreased by 16% compared to the chips. The carbon monoxide specific emissions were 2.78 g/MJ_d for pellets and 2.75 g/MJ_d for chips. On average, the cookstove released total suspended particulate matter between 74.11 and 122.70 mg/MJ_d. The cookstove low emissions are ascribed to the proper combustion air flow and the combustion chamber design, which favored the mixing between producer gas and combustion air.