Search

Activated carbon (AC) fabrication using agricultural waste biomass has been considered economical and sustainable. In this study, common reed (Phragmites australis)-derived activated carbon (CRPa-AC) was prepared via two consecutive stages, including pyrolysis and activation using K2CO3and employed as an absorbent for orange G (OG) removal. The CRPa-AC prepared at 1073 K and the K2CO3/char weigh ratio of 1.5 had the surface area = 549.7 m2/g and exhibited the removal efficiency of OG = 91.8%. The pseudo-second order kinetic and Langmuir isotherm models accurately described the adsorption of OG on the CRPa-AC. The maximum adsorption capacity of CRPa-AC (77.5 mg·g−1) surpassed that of other biomass-based AC previously published. Thermodynamic studies suggested that the OG adsorption on the CRPa-AC surface is endothermic. The good reusability of CRPa-AC after three regeneration cycles enabled its practical use in the OG removal. This study provided a typical example of converting waste into valuable material for wastewater treatment.

The current thermoremendable polyurethanes (PUs) based on reversible Diels–Alder (DA) chemistry featuring both good mechanical properties and efficient macrodamage healability are up to now built with the DA bonds located in the hard domains with restricted mobility, which hinders the DA reversibility. Thus, the healing process in these materials requires predissociation of DA bonds via the retro reaction at high temperatures (110–180 °C) followed by DA re-formation, which may compromise the material performance integrity. Here, we show a design of thermoset PUs containing dynamic DA entities engineered at the interface between the hard and soft domains that combine high modulus and toughness with mild-temperature-triggered molecular mobility, which is a prerequisite for efficient healing capability. This concept of molecular design enables PUs to have great mechanical properties (Young’s modulus ∼80–225 MPa, ultimate tensile strength ∼16–30 MPa, and toughness ∼26–96 MJ m–3) and simultaneously remarkable healing ability at mild temperatures (60–70 °C) of macroscratches, punctures, and complete cuts. The mechanical and healing properties can be tuned by varying the DA bond content. These materials are the first reported DA-based PU materials showing excellent healing efficiency at mild temperatures without compensation of their great mechanical properties.