Innovative Utilization of Triethanolamine for Enhanced Carbonation of Recycled Cement Paste Powder: Implementing Sustainable Solution Recycling Approaches

There has been numerous research focused on accelerating carbonation of recycled cement paste powder (RCPP). However, the carbonation rate is still low. This paper proposes an innovative utilization of triethanolamine (TEA) to accelerate carbonation of RCPP with sustainable solution recycling strategies. The results showed that the CO2 uptake of RCPP increased and then decreased as the increased concentration of TEA. Calcite and silica gel were the main carbonation products in carbonated RCPP. On the other hand, TEA solution with concentration of 0.010 M was chosen for recycling experiment and the results showed that the CO2 uptake of carbonated RCPP for 30 min decreased progressively with increasing number of cycles. Notably, by the 18th cycle, the CO2 uptake was comparable to that of control sample. Furthermore, the mechanism of accelerating the carbonation of TEA was provided, proving the feasibility of accelerated carbonation of RCPP by using TEA solution.