CO2 removal is one of the key technological requirements in biogas purification. A technique using a gas liquid mixing pump to capture CO2 and co-produce nano calcium carbonate was devised and tested in this work. The characteristic curves and CO2 absorption efficiency of the pump were investigated. The CO2 content of the end gas in all experiments was less than 2%, and the calcium carbonate samples showed that calcite was produced with a favorable particle size. A solution was proposed to deal with gas inlet blockage by preparing polyphenylene sulfide (PPS) polytetrafluoroethylene (PTFE) coating. The coating had superhydrophobicity, self-cleaning ability, a unique microstructure, and good adhesion to the substrate. The gas inlet coated with PPS PTFE could remain clean for at least 12 h, suggesting that the method used in this work was suitable. This work provides a novel approach for CO2 absorption and biogas purification.