Alkali Etching Hydrochar-Based Adsorbent Preparation Using Chinese Medicine Industry Waste and Its Application in Efficient Removal of Multiple Pollutants

The annual discharge (6–7 million tons per year) of Chinese medicine industry waste (CMIW) is large and harmful. CMIW with a high moisture content can be effectively treated by hydrothermal carbonization (HTC) technology. Compared CMIW, the volume number pores prepared hydrochar increased significantly after alkali etching (AE), they had abundant oxygen-containing functional groups. These properties provide physical chemical adsorption sites, improving adsorbent activity alkaline (AE-CMIW hydrochar). However, few studies have investigated organic dyes heavy metals in mixed solutions. This study proposed method coupling HTC AE to treat explored potential AE-CMIW remove metal ions from solution. We analyzed removal rates adsorbents their differences. results showed that lead ion, cadmium methylene blue could efficiently removed solution, more than 98%, 20–57%, 60–80%, respectively. were different mainly due various electrostatic interactions, adsorption, differences hydrating ion radius ions, group interactions between blue. provides technical for preparing multi-pollutant which enables efficient utilization solid achieves purpose treating waste.