Evaluating fluorescent dissolved organic matter released from wetland-plant derived biochar: Effects of extracting solutions

This study investigated the quantity and quality of dissolved organic matter (DOM) released from wetland-plant derived biochar under various extracting conditions (deionized water, 0.1 mol/L HCl, 0.1 mol/ff. NaOH, and 0.1 mol/L NaCl) by using fluorescence excitation-emission matrix (EEM) spectrophotometry with parallel factor analysis (PARAFAC). Concentrations of dissolved organic carbon (DOC) released from biochar extracted in different extracting solutions ranged from 0.69 g/L, to 1.22 g/L. with the total contents of 13.7-23.5 g DOC/kg. The average DOC content was highest in the alkaline solution and lowest in the deionized water. Three humic acid-like substances, one fulvic acid-like substance and one tyrosine-like substance were identified. The distributions of the identified components in DOM were distinctively different among various extracts, and humic acid-like components were the dominant materials. The extraction conditions could affect significantly humic acid-like and fulvic acid-like fluorescence. The results would be beneficial to understand the biochar's effects and processes in possible environmental applications. (C) 2018 Elsevier Ltd. All rights reserved.