TY - JOUR
T1 - Mg-Fe LDH-coated biochars for metal(loid) removal
T2 - Surface complexation modeling and structural change investigations
AU - Hudcová, Barbora
AU - Fein, Jeremy B.
AU - Tsang, Daniel C.W.
AU - Komárek, Michael
N1 - Funding Information:
Barbora Hudcová is thankful for the support from the Fulbright Commission and the Czech Science Foundation (project 21-23794J). The authors thank Adéla Šípková (CZU Prague), Hana Šnajdaufová (Institute of Chemical Process Fundamentals), Noemi Mészárosová (Institute of Geology, CAS, v.v.i.), Milan Erben (University of Pardubice) and Radek Fajgar (Institute of Chemical Process Fundamentals, CAS, v.v.i.) for their analytical work. Some analyses were conducted at the Center for Environmental Science and Technology at University of Notre Dame. Two journal reviews were helpful and significantly improved the presentation of the research.
Funding Information:
Barbora Hudcová is thankful for the support from the Fulbright Commission and the Czech Science Foundation (project 21-23794J). The authors thank Adéla Šípková (CZU Prague), Hana Šnajdaufová (Institute of Chemical Process Fundamentals), Noemi Mészárosová (Institute of Geology, CAS, v.v.i.), Milan Erben (University of Pardubice) and Radek Fajgar (Institute of Chemical Process Fundamentals, CAS, v.v.i.) for their analytical work. Some analyses were conducted at the Center for Environmental Science and Technology at University of Notre Dame. Two journal reviews were helpful and significantly improved the presentation of the research.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2022/3/15
Y1 - 2022/3/15
N2 - Although an increasing number of studies involving layered double hydroxide/biochar composites (LDH/BC) have been published recently, development of advanced modeling approaches of adsorption onto the composites and/or their testing and use in real soils and waters are rare. In this study, Zn(II) and As(V) sorption onto Mg-Fe LDH/BC composites was quantified using bulk sorption experiments, and the observed adsorption behavior was modeled using a non-electrostatic surface complexation model (NEM). In general, it was found that LDH is the main phase causing the removal of metal(loid)s from solution. In contrast, the contribution of BC was evident only in systems containing the most effective type of BC. Inner-sphere surface complexation was found to be the dominant adsorption mechanism at low Zn(II) and As(V) concentrations. In contrast, precipitation of Zn and formation of amorphous ferric arsenates contributed to the total metal removal at higher metal(loid) loadings. Surprisingly, increasing As(V) concentrations led to enhanced Mg leaching from the LDH/BC composites and to the destruction of the LDH structure. Nevertheless, all composite materials were stable at environmentally relevant metal(loid) concentrations. Our study is the first to use a surface complexation component additivity (CA) modeling approach to account for metal(loid) adsorption behavior onto LDH/BC composites, and we find that although site blocking does occur to some extent, the CA approach provides a reasonable estimate of the adsorption behavior across a wide range of pH conditions. Comprehensive studies such as this one are necessary in order to understand and optimize the behavior of novel composite materials before their subsequent use in environmental technologies.
AB - Although an increasing number of studies involving layered double hydroxide/biochar composites (LDH/BC) have been published recently, development of advanced modeling approaches of adsorption onto the composites and/or their testing and use in real soils and waters are rare. In this study, Zn(II) and As(V) sorption onto Mg-Fe LDH/BC composites was quantified using bulk sorption experiments, and the observed adsorption behavior was modeled using a non-electrostatic surface complexation model (NEM). In general, it was found that LDH is the main phase causing the removal of metal(loid)s from solution. In contrast, the contribution of BC was evident only in systems containing the most effective type of BC. Inner-sphere surface complexation was found to be the dominant adsorption mechanism at low Zn(II) and As(V) concentrations. In contrast, precipitation of Zn and formation of amorphous ferric arsenates contributed to the total metal removal at higher metal(loid) loadings. Surprisingly, increasing As(V) concentrations led to enhanced Mg leaching from the LDH/BC composites and to the destruction of the LDH structure. Nevertheless, all composite materials were stable at environmentally relevant metal(loid) concentrations. Our study is the first to use a surface complexation component additivity (CA) modeling approach to account for metal(loid) adsorption behavior onto LDH/BC composites, and we find that although site blocking does occur to some extent, the CA approach provides a reasonable estimate of the adsorption behavior across a wide range of pH conditions. Comprehensive studies such as this one are necessary in order to understand and optimize the behavior of novel composite materials before their subsequent use in environmental technologies.
KW - Arsenic
KW - Contaminant adsorption
KW - Engineered biochar
KW - Layered double hydroxides
KW - Surface complexation modeling
KW - Zinc
UR - http://www.scopus.com/inward/record.url?scp=85121912842&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2021.134360
DO - 10.1016/j.cej.2021.134360
M3 - Journal article
AN - SCOPUS:85121912842
SN - 1385-8947
VL - 432
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 134360
ER -