A Novel Eco-Friendly Circular Approach to Comprehensive Utilizing Bittern Waste and Oyster Shell

Efficient waste management, especially in relation to swaste reuse, has become a pressing societal issue. The waste bittern generated during salt production and discarded oyster shells present formidable environmental challenges and a waste of resources for some coastal regions. Therefore, this work developed a two-stage circular process for the environmentally friendly and efficient utilization of both waste materials. In the first stage, CO2 gas and an organic extraction phase comprising Tri(octyl-decyl)amine (R3N) and isoamyl alcohol were introduced into the waste bittern to obtain MgCO3 center dot 3H(2)O (s). The second stage involved reacting the reacted organic extraction phase with oyster shell powders to produce CaCl2 center dot 2H(2)O (s) and CO2 (g) and regenerate R3N. This work focused on investigating the yield of MgCO3 center dot 3H(2)O and the regeneration ratio of R3N, which are crucial indicators for the two stages involved in the process. The results indicate that, under optimal operating conditions, a maximum yield of 87% for MgCO3 center dot 3H(2)O was achieved, and the regeneration ratio of R3N reached 97%. Furthermore, the reaction mechanism and thermodynamic functions of the R3N regeneration process were elucidated as a crucial element in achieving a circular process. The findings of this work offer a sustainable solution to environmental pollution from waste bittern and oyster shells, and provide a promising avenue for green chemical production.

Automated summary

Efficient waste management is important for society, and this study developed a two-stage circular process for the utilization of waste bittern and discarded oyster shells. The results showed high yields of MgCO3•3H2O and a high regeneration ratio of R3N. This work provides a sustainable solution to environmental pollution and suggests a promising avenue for green chemical production.