Increasing straw surface functionalities for enhanced adsorption property

A simple low-temperature partial-oxidation process was demonstrated as an effective technology for reed straw modification towards environmental remediation. At an optimal temperature of 180 degrees C, the straw materials exhibited a remarkable colour change from light yellow to dark brown, increased methylene blue (MB) uptake by 1.8 times, enhanced removal efficiency from 34.5% to 92.8%, and a high yield of 77.2%. Spectroscopic characterization and Boehm titration proved that the amount of surface oxygen (O)-containing functional groups significantly increased after modification. A strong linear correlation (R-2 = 0.93) existed between total amounts of O-containing functional groups and MB uptake for modification temperatures below 180 degrees C, whereas blockage of the pore entrances and competition with metallic cations must be taken into account for samples generated from excess heating (>180 degrees C). These results provided insights into designing promising technologies for sustainable environmental management through reutilization of agricultural waste.