Production and evaluation of properties of waste-based carbon adsorbent

Abstract

This paper focuses on the study of the production method, evaluation of quality indicators and application of adsorbents based on wood and common polymer wastes. The co-pyrolysis technique of polyethylene, polypropylene, polyethylene terephthalate and other polymers with sawdust at the weight ratio of 1:1 and 1:2 and temperature 370−500 °C is used for the production of adsorbents. Influence of polymer and wood type on the product quality is discussed. For the composition of birch wood and polypropylene, linear models for the yield estimation and indicators of the porous structure of adsorbents, based on the experiment planning method, are proposed, which allow us to forecast their quality under the joint influence of their production factors. The adsorbent at 500 °C was also characterized by optical and electron microscopy, X-ray fluorimetry, infrared spectrometry and low-temperature nitrogen adsorption method: its surface area (Brunauer–Emmett–Teller) is 435 m2/g, surface area of micropores (t-plot) is 316 m2/g; the average pore diameter is 1.93 nm; the total pore volume is 0.20 cm3/g. The sample at 370 °C has maximal volume of pores sorbing 0.662 cm3/g of benzene and 0.703 cm3/g of tetrachlormethane and expressed hydrophobic properties; these values are superior to those of birch activated carbon twice. Its use for the vapor recovery of benzene from the airflow was evaluated, which showed its high activity (322 mg/g) and superiority over commercial activated carbon. An approximate ecological and economic evaluation of this adsorbent production has been carried out, demonstrating its profitability and environmental effectiveness.