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Homogeneous precipitation was proposed to prepare hydrated manganese dioxide (HMO) with KMnO4 as oxidant, NaCl as reductant and HNO3 as reaction auxiliary. HMO was applied to remove Cd(II) and the effect of contact time, initial concentration, adsorbent dose and pH value on adsorption efficiency were investigated. The removal mechanisms at various pH values were analysed in detail. Adsorption thermodynamics parameters were calculated as ΔG < 0, ΔH > 0 and ΔS > 0, which meant that the adsorption process was endothermic. The result of adsorption kinetics indicated the adsorption process conformed to pseudo-second-order kinetics. When adsorbing Cd(II) with initial concentration equaling 100 mg·L−1, the activation energy (Ea) was 62.740 kJ·mol−1. The Langmuir model could describe adsorption behaviour on HMO better than the Freundlich model, indicating that the adsorption sites of HMO were homogeneous and that single-layer adsorption was a dominant way in this process. The maximum adsorption capacity of Cd(II) on MnO2 calculated by the Langmuir model was 267 mg·g−1. The adsorbent HMO could be recycled and reused for several times with a high efficiency above 70% by adding HCl. SEM, EDS, FTIR and XPS were used to analyse the mechanisms of removal of Cd(II) at pH = 3,7 and 10. The mechanisms included electrostatic attraction, ion exchange and chemical precipitation. With pH increasing, the zeta potential decreased and the surface negative charge increased, promoting Cd(II) removal through enhanced electrostatic attraction. Meanwhile, ion exchange mechanisms including inner-sphere complexation and outer-sphere complexation occurred during adsorption process at different pH. [ABSTRACT FROM AUTHOR]

Natural bio‐based materials used in wound dressings have been continuously developed in recent years, and have certain advantages in water retention, biocompatibility, and therapeutic properties. Konjac glucomannan (KGM) is a kind of plant polysaccharide with good cell compatibility and gel properties. Various gels obtained by modification of KGM through physical and chemical methods have great application potential in wound excipients. In the past few years, various KGM‐based wound barrier materials such as hydrogels, xerogel, microspheres, films, and fibers have been continuously researched and developed. The combination of KGM and other polymers can improve the problem of poor mechanical properties and give it new functional properties, which is beneficial to the moisturizing of the wound surface and the release of drugs to promote wound healing. This article reviews the physicochemical properties of KGM and the latest developments in KGM‐based composite gels, reveals the relationship between molecules in KGM‐based composite gels, and looks forward to the research and development prospects of KGM‐based composites in wound dressings. [ABSTRACT FROM AUTHOR]