Adsorption of Difluoromethane (HFC-32) onto phenol resin based adsorbent: Theory and experiments

Adsorption and desorption of difluoromethane (HFC-32) onto newly developed phenol resin based adsorbent (SAC-2) have been measured experimentally for the isotherm temperatures ranging from 30 °C to 130 °C and pressure up to 3 MPa. A magnetic suspension balance based adsorption measurement unit is used to measure adsorption uptake gravimetrically. The presented SAC-2/HFC-32 pair has adsorption uptake as high as 2.23 kgref/kgads (excess adsorption) and 2.34 kgref/kgads (absolute adsorption) at 30 °C and 1.67 MPa. To the best of our knowledge, it is the highest HFC-32 adsorption capacity onto any adsorbent available in the literature. The experimental data of adsorption/desorption isotherms show that there is no hysteresis for the studied pair. The data have been fitted with Tóth; Dubinin-Astakhov (D-A); and Guggenheim, Anderson, De-Boer (GAB) adsorption isotherm models. The parameters of adsorption isotherm models are optimized by nonlinear optimization technique. The D-A model fits the experimental data precisely as compared to other models. In addition, numerical values of isosteric heat of adsorption have also been extracted by means of Clausius-Clapeyron equation using adsorption isotherm models.