Catalytic hydrochars were produced by hydrothermal carbonization (HTC) of compost derived from Municipal
Solid Waste (MSW). The HTC process was studied through a Design of Experiments to assess the influence of the variables: (i) time (1–5 h), (ii) load of compost (1–4 g in 30 mL) and, (iii) temperature (150–230 ◦C). Total organic carbon (TOC), conductivity and volume variation of the liquid fraction, as well as the mass and carbon content of the solid fraction (hydrochars), were the evaluated responses. Reliable models (R2 > 0.95 and p-values < 0.05) were fitted to the responses, and the load of compost was found as the most significant variable influencing the process. The Fenton reaction was proposed as an effective treatment of the liquid fraction generated from HTC of compost. A TOC abatement of 73% was obtained after 24 h of reaction under the studied operating conditions (80 ◦C, initial pH 3.0, 100 mg L 1 Fe+2 and two times the stoichiometric amount of H2O2 needed for the complete mineralization of the TOC present in the liquid fraction). The hydrochars produced show high catalytic activity in the decomposition of H2O2, a reaction of interest in a variety of chemical processes, 100% of H2O2 degradation being obtained after 6 h of reaction.
This work was financially supported by project “VALORCOMP -
Valorizaci´on de compost y otros desechos procedentes de la fracci´on
org´anica de los residuos municipales”, with reference 0119_VALORCOMP_
2_P, through FEDER under Program INTERREG; Base Funding -
UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by
national funds through FCT/MCTES (PIDDAC); CIMO (UIDB/00690/
2020) through FEDER under Program PT2020, and national funding by
FCT, Foundation for Science and Technology, through the individual
research grant SFRH/BD/143224/2019 of Fernanda Fontana Roman.
