Point of Zero Charge determination of ten standard biochars for the removal of methylene blue from aqueous solutions
September 15-20, 2019
This study describes the determination of the point of zero charge (PZC) of ten standard biochars (BC), supplied by the UK Biochar Research Centre (UKBRC), using the salt addition method, in order to select suitable biochar(s) for methylene blue removal from aqueous solutions. The initial pH (pHi) was adjusted in a range of 3 to 13 using NaOH and HNO3 solutions. The experiments employed a biochar dose of 10 g L-1. The final pH values (pHf) were recorded in the remaining suspensions after a 24-hour contact time at 120 rpm. The difference between pHi and pHf (∆pH) was plotted against pHi values and the pH at PZC (pHPZC) corresponded to the point of intersection in the resulting curve. The results obtained in 0.1 mol L-1 NaNO3 were the following: PZC at 7.24 and 8.53 for rice husk biochar (RH), the first obtained at 550 °C pyrolytic temperature and the latter at 700 °C (RH550 and RH700); PZC at 8.81 and 9.46 for oil seed rape straw pellets biochar obtained at 550 °C and 700 °C (OSR550 and OSR700), respectively; PZC at 9.24 and 9.84 for wheat straw pellets biochar (WS550 and WS700, respectively); PZC at 8.98 and 8.94 for Miscanthus straw pellets biochar (MSP550 and MSP700, respectively); and PZC at 6.73 and 7.15 for soft wood pellets biochar (SWP550 and SWP700, respectively).
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Ondrej Masek, Leonardo Betini Sebton, Suzimara Rovani, Nilce Ortiz, Jorge Albero Soares Tenório, and Ondrej Masek, "Point of Zero Charge determination of ten standard biochars for the removal of methylene blue from aqueous solutions" in "Bio-Char II: Production, Characterization and Applications", Franco Berruti, Western University, London, Ontario, Canada David Chiaramonti, RE-CORD, University of Firenze, Italy Ondrej Masek, University of Edinburgh, Edinburgh, United Kingdom Manuel Garcia-Perez, Washington State University, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/biochar_ii/4