A nanoscale observation to explain the discrepancy of electron exchange capacities between biochar containing comparable surface redox-active moieties  

作　　者：Shasha Li Liming Shao Hua Zhang Xuemin Lu Fan Lü Pinjing He 

机构地区：[1]State Key Laboratory of Pollution Control and Resource Reuse,Tongji University,Shanghai 200092,People’s Republic of China [2]Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,People’s Republic of China [3]Institute of Waste Treatment and Reclamation,Tongji University,Shanghai 200092,People’s Republic of China [4]Shanghai Multi-Source Solid Waste Collaborative Treatment and Energy Engineering Technology Research Center,Shanghai,People’s Republic of China

出　　处：《Biochar》2022年第1期503-517,共15页生物炭（英文）

基　　金：the National Key Research&Development Program from Ministry of Science and Technology of China[Grant Number 2018YFD1100600];the Key Research&Development Program from Science Technology Department of Zhejiang Province[2021C03024].

摘　　要：Biochar,possessing electron exchange capacities(EEC),is generally involved in environmental redox reactions due to the presence of redox-active moieties(RAMs).The phenomenon that chars containing comparable RAMs possess differential EEC revealed that the accessibility of RAMs is important to the redox properties.However,many studies have focused on the type of RAMs,whereas the distribution has been insufficiently investigated.Herein,we achieved nanoscale observation of electroactive moieties on the surface of six chars using a conductive atomic force microscope.For the two specific kinds of chars with submicron particles and opposite current distributions,the submicron particles took up only 1-4‰wt of biochar accounting for approximately 30-50%of electron-donating capacity(EDC),and electron-accepting capacity(EAC)became 87%and 1.40 times as before after removing submicron particles,respectively.Meanwhile,the combined impact of RAMs and surface topography(that uneven distribution of RAMs resulted in outstanding EEC by enhancing accessibility)was clarified.Furthermore,direct evidence of the link between char structure and EEC(that condensed aromatic structures were indispensable to EAC while both heteroatoms and amorphous aromatics contributed to EDC)was established.These findings can aid in understanding the functions of biochar in biotic and abiotic redox processes.

关 键 词：BIOCHAR Pyrogenic chars Redox property Electron exchange capacity C-AFM 

分 类 号：TB383[一般工业技术—材料科学与工程]