Nano-Silver-Loaded Activated Carbon Material Derived from Waste Rice Noodles: Adsorption and Antibacterial Performance
Guanzhi Ding, Guangzhi Qin, Wan-Ying Ying, Pengyu Wang, Yang Yang, Chenyu Tang, Qing Liu, Minghui Li, Ke Huang, Shuoping Chen
Abstract
This study demonstrates, for the first time, the conversion of waste rice noodles (WRN) into a cost-effective, nano-silver-loaded activated carbon (Ag/AC) material capable of efficient adsorption and antibacterial activity. The fabrication process began with the conversion of WRN into hydrothermal carbon (HTC) via a hydrothermal method. Subsequently, the HTC was combined with silver nitrate (AgNO3) and sodium hydroxide (NaOH), followed by activation through high-temperature calcination, during which AgNO3 was reduced to nano-Ag and loaded onto the HTC-derived AC, resulting in a composite material with both excellent adsorption properties and antibacterial activity. The experimental results indicated that the incorporation of nano-Ag significantly enhanced the specific surface area of the Ag/AC composite and altered its pore size distribution characteristics. Under optimized preparation conditions, the obtained Ag/AC material exhibited a specific surface area of 2025.96 m2/g and an average pore size of 2.14 nm, demonstrating effective adsorption capabilities for the heavy metal Cr(VI). Under conditions of pH 2 and room temperature (293 K), the maximum equilibrium adsorption capacity for Cr(VI) reached 97.07 mg/g. The adsorption behavior of the resulting Ag/AC fitted the Freundlich adsorption isotherm and followed a pseudo-second-order kinetic model. Furthermore, the Ag/AC composite exhibited remarkable inhibitory effects against common pathogenic bacteria such as E. coli and S. aureus, achieving antibacterial rates of 100% and 81%, respectively, after a contact time of 4 h. These findings confirm the feasibility of utilizing the HTC method to process WRN and produce novel AC-based functional materials.