Biochar produced from oak sawdust by Lanthanum (La)-involved pyrolysis for adsorption of ammonium (NH4+), nitrate (NO3−), and phosphate (PO43−)

Recovery of nutrients from biogas digestate with biochar and clinoptilolite

“…Our results for orthophosphate removal efficiency were in line with other studies which reported removal efficiencies of between 38 % and 95 % (Sarkhot et al, 2013;Zeng et al, 2013). We did not investigate the mechanisms involved in orthophosphate removal by biochar, but potential mechanisms suggested for orthophosphate removal from liquid solutions include phosphate adsorption to MgO on the biochar surface (Yao et al, 2011), precipitation reactions between phosphate and Ca + and Mg + ions (Wang et al, 2015c), anion exchange with surface hydroxyl groups (Sarkhot et al, 2013) and electrostatic interaction of phosphate anions with charged hydroxide surfaces (Chen et al, 2011).…”

“…Reported values for the amount of ammonium removal per g vary between 0.10 and 5.40 mg g -1 from synthetic solutions with wood biochar (Hollister et al, 2013;Hina et al, 2014;Jassal et al, 2015;Wang et al, 2015aWang et al, , 2015c. Few studies have reported ammonium removal from manure or manure digestates, which usually have a higher ammonium concentration and organic matter content than synthetic solutions.…”

“…Effect of the initial loading ratio on nutrient and organic matter removal Several potential mechanisms for ammonium removal by biochar from liquid solutions have been proposed: cation exchange with cations such as Ca 2+ , Mg 2+ , K + , Na + in biochar (Hale et al, 2013;Sarkhot et al, 2013;Zeng et al, 2013;Cui et al, 2016), chemical reactions with (oxygen-containing) surface functional groups (Kizito et al, 2015;Wang et al, 2015aWang et al, , 2015cCui et al, 2016), surface areadependent physical diffusion and physical entrapment of NH4 + in biochar pores (Clough et al, 2013;Kizito et al, 2015), co-adsorption with soluble organic matter (Lehmann et al, 2002;Sarkhot et al, 2013) and struvite (MgNH4PO4.6H2O) precipitation on biochar (Cui et al, 2016). Lehmann et al (2002) attribute ammonium adsorption to the coadsorption with soluble organic matter.…”

“…Sorbent materials enriched in nutrients can be considered to be nutrient carriers, which can subsequently be used as a fertiliser in agricultural fields. Biochar has been suggested as a sorbent for the removal of ammonium (Mukherjee et al, 2011;Hale et al, 2013;Hollister et al, 2013;Sarkhot et al, 2013;Hina et al, 2014;Wang et al, 2015a) and phosphate (Yao et al, 2013;Zeng et al, 2013;Wang et al, 2015c) from various wastewaters. Biochar has also attracted growing interest as an effective sorbent for removing organic contaminants due to its porous structure and large surface area (Chen et al, 2011;Ahmad et al, 2014;Mohan et al, 2014;Oh & Seo, 2015;Wang et al, 2015b).…”

“…Both inorganic and organic materials have been used successfully for nutrient sorption. Clinoptilolite (a natural zeolite) has been used to remove nutrients from source-separated urine (Ganrot et al, 2007;Beler-Baykal et al, 2011;Allar & Beler Baykal, 2015) and several studies have described the adsorption of ammonium and other nutrients to biochar, a carbonaceous product from the pyrolysis of biomass (Eldridge & ChengRong, 2010;Hale et al, 2013;Sarkhot et al, 2013;Gai et al, 2014;Jassal et al, 2015;Wang et al, 2015c).…”