Optimization of the Removal of Toluene in the Air by Activated Carbon / ZIF-8 Metal-Organic Framework

In this research, the objective was to optimize the operating conditions for removing toluene from the air stream using a composite of activated carbon (AC) and ZIF-8 metal-organic framework (MOF). The experimental design involved defining the input variables (type of adsorbent, mass of adsorbent, air flow rate, temperature, and relative humidity) and response variables (adsorption capacity and breakthrough time). The study consisted of six steps: 1) synthesis of ZIF-8 MOF and AC@ZIF-8 composite, 2) creation of the experimental design using Central Composite Design (CCD), 3) structural analysis tests, 4) experimental runs, 5) statistical analysis, and 6) experimental verification tests. The 2FI model was determined to be the most suitable for predicting adsorption capacity and breakthrough time. The optimized run achieved a toluene inlet concentration of 300 ppm, AC@ZIF-8 as the adsorbent type, an air temperature of 27 & ring;C, air relative humidity of 29%, adsorbent mass of 9 mg, and an airflow rate of 250 ml/min. The breakthrough time for 100% composite utilization was 18.6 hours. The results of toluene adsorption using AC@ZIF-8 showed a 50% higher breakthrough time and adsorption capacity compared to the other two adsorbents (AC and ZIF-8). In conclusion, the AC@ZIF-8 composite is well-suited for efficiently removing and adsorbing toluene from the air stream. Considering the high cost of MOF synthesis and the limitations of activated carbon in selectively removing volatile organic compounds, the AC@ZIF-8 composite can be a viable option for air adsorption and purification processes.