Novel rapid adsorption evaluation for activated carbon via electrical resistance with temperature-humidity compensation

Volatile organic compounds (VOCs) endanger the environment and human health. Among various control methods, activated carbon (AC) adsorption has become an industrial mainstream due to its high removal efficiency. The traditional iodine value (IV) assessment method is time-consuming and difficult to apply in real time. It is important to note that AC, after adsorbing VOCs, is classified as hazardous waste. This study explores indirectly characterizing the adsorption performance of AC through electrical resistance (ER) measurements. Experiments conducted at 26°C and 50% RH using an optimized device (with dimensions of 78 × 157 × 72 mm, equipped with graphite electrodes and applying a pressure of 750 Pa) revealed a significant negative correlation between ER and IV: ER increases monotonically as IV decreases, and both stabilize when the adsorption reaches saturation. The ER of the initial AC is significantly affected by the environment: for every 15% increase in relative humidity, ER decreases by 27.2%; for every 10°C increase in temperature, ER increases by 1.5 Ω. Based on this, a temperature-humidity compensation model was established to correct environmental interferences, with an IV prediction coefficient of determination (R2) of 0.85. This ER-IV correlation, combined with the compensation model, provides a new method for the rapid assessment of the adsorption performance of AC; further optimization is required to improve its universality and accuracy under different conditions.