No abstract

No abstract

In this study, the CeO2-Fe2O3 mixed oxide catalysts have been prepared by combustion method using gel-created tartaric acid. The ability of effective carbon monoxide (CO) oxidation to carbon dioxide (CO2) by CeO2-Fe2O3 catalyst under low-temperature conditions was also demonstrated. The calcined CeO2-Fe2O3 material has a porous honeycomb structure and good gaseous absorption-desorption ability. The solid solution of CeO2-Fe2O3 mixed oxides was formed by the substitution of Fe+3 ions at some Ce4+ ion sites within the CeO2 crystal lattice. The results also showed that the calcination temperature and the molar ratio of Ce3+ ions to Fe3+ ions (CF) affected the formation of the structural phase and the catalytic efficiency. The catalytic properties of the CeO2-Fe2O3 mixed oxide were good at the CF ratio of 1 : 1, the average crystal size was near 70 nm, and the specific surface area was about 20.22 m2.g-1. The full conversion of CO into CO2 has been accomplished at a relatively low temperature of 270 °C under insufficient O2 conditions.

No abstract

Many plant species that are known as silicon (Si) accumulators can form a so-called phytolith (silicified structure) within their organs. Together with organic matter, potassium (K) has also been found in phytolith structures (phytK). Annually, billions of tons of Si-rich biomass wastes are cycled in agricultural and natural systems worldwide. However, the fate of the phytolith and its phytK have not been fully understood. This study aims to examine the dynamic release of phytK from phytoliths of reed, rice straw, maize and sugarcane leaf samples. Phytoliths obtained from the biomasses by performing heat treatment at 600 °C were used for batch kinetic experiments. The phytK was found to have 26.3 ± 10.6, 98.9 ± 17.4, 24.9 ± 14.8 and 58.8 ± 13.9 mg Kg −1 for the reed, rice straw, sugarcane and maize leaves, respectively. These phytK amounts comprised at least >45% of the total K budgets in the biomasses and they were observed to be gradually released with time. The retardation of phytK was tightly related to the dissolution rate of phytoliths. The findings highlight that phytoliths carry certain amounts of K, potentially serving as a slow-release K source for soil and crops. Additionally, this short communication suggests a premise for the development of refinery strategies or extending the range of agronomic options for billions of tons of Si-rich biomass wastes worldwide.