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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Functional Foods Research » Research » Publications at this Location » Publication #332144

Research Project: Evaluation of the Chemical and Physical Properties of Low-Value Agricultural Crops and Products to Enhance Their Use and Value

Location: Functional Foods Research

Title: Chemical and physical properties of Paulownia elongata biochar modified with oxidants for horticultural applications

item Vaughn, Steven
item Kenar, James - Jim
item Tisserat, Brent
item Jackson, Michael - Mike
item JOSHEE, NIRMAL - Fort Valley State University
item VAIDYA, BRAJESH - Fort Valley State University
item Peterson, Steven - Steve

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2016
Publication Date: 12/17/2016
Publication URL:
Citation: Vaughn, S.F., Kenar, J.A., Tisserat, B., Jackson, M.A., Joshee, N., Vaidya, B.N., Peterson, S.C. 2017. Chemical and physical properties of Paulownia elongata biochar modified with oxidants for horticultural applications. Industrial Crops and Products. 97:260-267.

Interpretive Summary: This research shows that modifying biochar (agricultural charcoal) derived from Paulownia wood is not necessary for the biochar to have desirable characteristics for horticultural applications such as a component of greenhouse potting media or as a replacement for peat in golf greens. Peat moss is a common component of potting media as well as a component with sand during the construction of new golf greens. However, peat moss decomposes over time, making its effectiveness less over time. Because biochar is extremely resistant to decomposition, it should have extended longevity for horticultural applications. Several studies have found that treating various biochars with oxidizing chemicals improved properties important for their use in horticultural applications. In this study Paulownia biochar was treated with several oxidizing chemicals and then examined for chemical and physical changes. For most of these properties, the untreated biochar was superior to the chemically-modified biochars. Based on these results biochar from Paulownia wood should have excellent properties as a component of potting media or for golf course greens.

Technical Abstract: Treatment of biochar with oxidants such as acids and hydrogen peroxide has been shown to alter porosity, increase adsorption of chemicals, and introduce functional groups on the biochar surfaces, all of which are desirable for their use in horticultural applications. Biochar was produced from the pyrolysis of wood from seven-year-old Paulownia elongata (PE) trees using a top-lit updraft design stove. PE biochar was subsequently treated with 30% (v/v) sulfuric acid, 30% (w/v) oxalic acid, and 10 and 30% (w/w) H2O2. After thorough rinsing to remove residual acids and H2O2, biochars were examined for chemical and physical properties. All of the biochars had high carbon percentages, due to the high temperatures (>1000 oC) reached during pyrolysis. Surface areas, micropore surface areas, % micropore surface areas, pH values, cation exchange capacities and electrical conductivities decreased with all oxidant treatments. Analysis of surface functionality by ATR-FTIR showed limited changes resulting from the treatments. TPO/MS analysis showed that all treatments resulted in chars with higher oxidation temperatures suggesting that these are more stable toward oxidation. Unlike reports of biochar derived from different feedstocks and different pyrolysis methods, it appears that treatment of PE biochar with oxidants is unnecessary for its use in horticultural applications.