Hidden carbon emission in cross-provincial trade has vital impacts on regional gross carbon emission and coordinated development, a key factor needed to be considered when planning carbon trade and reaching “carbon peaking” and “carbon neutralization” objectives. This paper uses multiple regional input/output model on hidden carbon in cross-provincial trade and China’s 2012 and 2017 input/output data to study the temporal-spatial changes of hidden carbon emission of Shanxi cross-provincial trade, and employes carbon-transferring-responsibility-sharing to estimate Shanxi’s responsibilities in hidden carbon emission amid its cross-provincial trade, and applies structural method to analyze the factors impacting hidden carbon emission changes in Shanxi’s cross-provincial trade. Shanxi’s net-transferred-in hidden carbon emission has increased by 12.490 kt during 2012 to 2017, while its net-transferred-in provinces numbers dropped to 25 from 28. Those having less net-transferred-out are concentrating in northwestern and southwestern China. Structural analysis suggests scaling effect be the leading factor increasing transferred-in and -out of Shanxi’s hidden carbon emission. This paper presents suggestions on optimizing Shanxi’s hidden carbon emission policies of its cross-provincial trade.

This paper uses sulfur autotrophic denitrification to treat nitrate\|polluted underground water so as to explore the impacts of Cu2+ and Fe2+ ion addition on denitrification. Addition of Fe2+ ions at 0.10% and 0.20% or Cu2+ ion at 0.05% can effectively remove the nitrate and promote the denitrification rate. After 216 hours in reaction, nitrate removal rate reaches at 97%, up to 99%. Appropriate addition of metal ions may significantly reduce the accumulation of sulfates. In the entire reaction, composite material provides sufficient alkalinity for denitrification system, which guarantees the efficiency of denitrification reaction.