Removing Gaseous NH3 Using Biochar as an Adsorbent

Agriculture

Kyoung S. Ro³  Isabel M. Lima⁴  Guidqopuram B. Reddy²  Michael A. Jackson⁵  Bin Gao¹ 

[1] Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA; E-Mail:;Department of Natural Resources, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA; E-Mail:;USDA-ARS Coastal Plains Soil, Water and Plant Research Center, Florence, SC 29501, USA;USDA-ARS Southern Regional Research Center, New Orleans, LA 70124, USA; E-Mail:;USDA-ARS National Center for Agricultural Utilization Research, Peoria, IL 61604, USA; E-Mail:

关键词: gaseous ammonia;    biochar;    adsorption;    activation;    regeneration;   

DOI  :  10.3390/agriculture5040991

来源: mdpi

【 摘 要 】

Ammonia is a major fugitive gas emitted from livestock operations and fertilization production. This study tested the potential of various biochars in removing gaseous ammonia via adsorption processes. Gaseous ammonia adsorption capacities of various biochars made from wood shaving and chicken litter with different thermal conditions and activation techniques were determined using laboratory adsorption column tests. Ammonia adsorption capacities of non-activated biochars ranged from 0.15 to 5.09 mg·N/g, which were comparable to that of other commercial activated carbon and natural zeolite. There were no significant differences in ammonia adsorption capacities of steam activated and non-activated biochars even if the surface areas of the steam activated biochars were about two orders of magnitude greater than that of non-activated biochars. In contrast, phosphoric acid activation greatly increased the biochar ammonia adsorption capacity. This suggests that the surface area of biochar did not readily control gaseous NH₃ adsorption. Ammonia adsorption capacities were more or less linearly increased with acidic oxygen surface groups of non-activated and steam-activated biochars. Phosphoric acid bound to the acid activated biochars is suspected to contribute to the exceptionally high ammonia adsorption capacity. The sorption capacities of virgin and water-washed biochar samples were not different, suggesting the potential to regenerate spent biochar simply with water instead of energy- and capital-intensive steam. The results of this study suggest that non-activated biochars can successfully replace commercial activated carbon in removing gaseous ammonia and the removal efficiency will greatly increase if the biochars are activated with phosphoric acid.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.