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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #379476
Research Project: Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Physiochemical characterization of biochars from six feedstocks and their effects on the sorption of atrazine in an organic soil

Author
item GAFFAR, SHAGUFTA - Florida International University
item DATTAMUDI, SANKU - Florida International University
item BABOUKANI, AMIN - Florida International University
item CHANDA, SAOLI - Florida International University
item Novak, Jeffrey
item Watts, Donald - Don
item WANG, CHUNLEI - Florida International University
item JAYACHANDRAN, KRISHNASWAMY - Florida International University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/7/2021
Publication Date: 4/9/2021
Citation: Gaffar, S., Dattamudi, S., Baboukani, A.R., Chanda, S., Novak, J.M., Watts, D.W., Wang, C., Jayachandran, K. 2021. Physiochemical characterization of biochars from six feedstocks and their effects on the sorption of atrazine in an organic soil. Agronomy. https://doi.org/10.3390/agronomy11040716.
DOI: https://doi.org/10.3390/agronomy11040716

Interpretive Summary: Atrazine is one of the most commonly used herbicides to combat weeds in agricultural production. In recent decades, atrazine has been commonly detected in soil, drinking water aquifers, shallow groundwater and in surface water. This is an important concern, because atrazine has been recognized as an endocrine disruptor in humans and impacts the central nervous systems of mammals and aquatic invertebrates. Therefore, a viable issue remains to control the movement of atrazine from soils into water bodies. Sorption is an effective solution for controlling the movement of atrazine. Sorption of atrazine is enhanced by using biochar. Biochar is a byproduct of thermal pyrolysis of carbon rich biomass. The effects of biochar on atrazine adsorption is a well-researched topic, however, the comparative analysis of different biochar feedstocks on sorption kinetics of atrazine is limited. We conducted an experiment where atrazine sorption effects by 12 different biochars were examined. We found that biochars made from coconut husk performed best for controlling sorption behavior of atrazine in soil. Other biochars from native plant species (loblolly pine and pecan shell) also performed well and about 7-10% better in increasing atrazine adsorption compared to biochars from invasive plant species (Australian pine and Brazilian pepper). Our results indicate that if biochar is chosen as an atrazine sorption compound, then care should be exercised to select the better feedstock for that purpose.

Technical Abstract: Biochar, produced from pyrolyzed biomass, has increasingly been considered as a cost-effective agent to reduce the loss of organic contaminants from soil profile through its high sorption potentiality. Application of biochars in agricultural soil is expected to reduce groundwater contamination of atrazine, a widely used herbicide in the U.S., and therefore, sustain environmental quality and reduce human health issues caused by atrazine. This study was conducted to characterize the biochars produced from six different feedstocks (including invasive plant species) and to investigate their comparative ability to remove and retain atrazine in an organic rich soil. Feedstocks used in this study included Australian pine (AP), Brazilian pepper (BP), coconut husk (CH), cypress (Cy), loblolly pine (L), and pecan shell (P). The biochars were categorized based on the feedstock and production temperatures (350 degree Celsius and 500 Celsius), such as, AP350 indicated the biochar produced from Australian pine with a pyrolysis temperature of 350 degrees Celsius. Freundlich isotherms were used to explain the adsorption and desorption behaviors of atrazine. Higher pyrolysis temperature increased specific surface area (5 times), total pore volume (2.5 times), and aromaticity (1.4 times) of the biochars, however, no significant changes in atrazine adsorption was observed when temperature increased from 350 degrees Celsius to 500 degree Celsius. It was also found that coconut husk produced the most effective biochars (CH350 and CH500), which adsorb 8-12% higher atrazine than soils without biochar (unamended). In particular, among all 12 biochars, CH350 performed the best (Kd ads = 13.80, KOC = 153.63, Kd des = 16.98) and had significantly higher (p < 0.05) adsorption than unamended soil possibly resulting from the highest cation exchange capacity (CEC) of CH350 (16.32 centimol per kg). Additionally, biochars made from plant species native to South Florida, USA (loblolly pine and pecan shell) had 7-10% higher sorption of atrazine compared to the biochars produced from non-native invasive species (AP and BP) suggesting that biochars produced from native species perform better in the same agroclimatic regions where they grow. The overall Kd desorption values for atrazine were found to be greater than the Kd adsorption values indicating a considerable amount of the atrazine that was adsorbed by the biochar amended soils was retained following desorption.