Assessing the performance of clinoptilolite for controlling and releasing ammonium in agricultural applications

To develop soil holding capacity of NH4+ and reduce the energy consumption of industrial fertilizer production, different dosages of clinoptilolite mixed with soil were used to absorb NH4+, which was also simulated using Freundlich and Langmuir equation under different conditions. The results showed that NH4+ adsorption of clinoptilolite-amended soil changed from multilayer adsorption to single-layer adsorption with the increase in clinoptilolite application rates. The optimal ratio of clinoptilolite applied to the soil for high adsorption efficiency was 0.01g 10g(-1). The co-existence of Na+ and K+ increased the NH4+ adsorption capacity of clinoptilolite-amended soil relative to the existence of single Na+. This showed that K+ was less competitive towards NH4+ than Na+. Decreasing water quantity, which increased the total soil adsorption capacity by a factor of 2 to 3, had the most significant effect and helped regulate the release of nitrogen in clinoptilolite-amended soil. In sum, clinoptilolite can enhance soil nitrogen holding capacity, which shows great potentials to reduce the energy consumption of industrial urea production. (C) 2021 TheAuthor(s). Published by Elsevier Ltd.

Automated summary

Clinoptilolite mixed with soil can enhance soil nitrogen holding capacity, with an optimal application ratio of 0.01g 10g(-1) for high adsorption efficiency. The co-existence of Na+ and K+ increases NH4+ adsorption capacity, with K+ being less competitive towards NH4+ than Na+. Decreasing water quantity significantly increases total soil adsorption capacity and regulates nitrogen release in clinoptilolite-amended soil.