Elucidating the Role of Sulfide on the Stability of Ferrihydrite Colloids under Anoxic Conditions

He, Leiyu1; Xie, Lin3; Wang, Dengjun4; Li, Wenlu5; Fortner, John D.5; Li, Qianqian1; Duan, Yanhua1; Shi, Zhenqing6; Liao, Peng1,2; Liu, Chongxuan1,2

2019-04-16

10.1021/acs.est.8b05694

ENVIRONMENTAL SCIENCE & TECHNOLOGY   影响因子和分区

0013-936X

1520-5851

While the reaction mechanisms between ferrihydrite and sulfide are well-documented, the role of redox reactions on the particle particle stability of ferrihydrite colloids is largely overlooked. Such reactions are critical for a number of (bio)geochemical processes governing ferrihydrite-based colloid processing and their associated role in nutrient and contaminant subsurface dynamics. Taking a fundamental colloid chemistry approach, along with a complementary suite of characterization techniques, here, we explore the stability mechanisms of ferrihydrite colloids over a wide range of environmentally relevant sulfide concentrations at pH 6.0. Results show that sulfide lowered the stability of both ferrihydrite colloids in a concentration-dependent fashion. At lower sulfide concentrations (15.6-62.5 mu M), ferrihydrite colloids are apparently stable, but their critical coagulation concentration (CCC) in NaCl linearly decreases with increasing sulfide concentration. This is attributed to the formation of negatively charged elemental sulfur (S(0)) nanoparticles on the surfaces of positively charged ferrihydrite, intensifying the electrostatic attractions between oppositely charged regions on adjacent ferrihydrite surfaces. Further increasing sulfide concentration generates more S(0) attaching to the ferrihydrite surface. This results in effective surface charge neutralization and then subsequent charge reversal, leading to extensive aggregation of ferrihydrite (core) colloids. Interestingly, for the ferrihydrite colloids with higher hydrodynamic diameter, aggregation rates linearly decreases with increasing sulfide concentration from 156.3 to 312.5 mu M, which is likely due to the formation of substantial amounts of negatively charged S(0) and FeS. Findings highlight the significance of sulfidation products in controlling the stability of ferrihydrite colloids in sulfidic environments.

SCI ; EI

英语

NI论文

第一 ; 通讯

Southern University of Science and Technology (SUSTC)[G01296001]

Engineering ; Environmental Sciences & Ecology

Engineering, Environmental ; Environmental Sciences

WOS:000465190300017

AMER CHEMICAL SOC

20191406721255

Agglomeration ; Colloid chemistry ; Iron compounds ; Redox reactions ; Sodium chloride ; Stability ; Sulfur compounds

Colloid Chemistry:801.3 ; Chemical Reactions:802.2 ; Chemical Operations:802.3

ENVIRONMENT/ECOLOGY

Web of Science

1.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Guangdong Prov Key Lab Soil & Groundwater Pollut, Shenzhen 518055, Peoples R China
2.Southern Univ Sci & Technol, Sch Environm Sci & Engn, State Environm Protect Key Lab Integrated Surface, Shenzhen 518055, Peoples R China
3.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
4.US EPA, Natl Res Council Resident Res Associate, Ada, OK 74820 USA
5.Washington Univ, Dept Energy Environm & Chem Engn, St Louis, MO 63130 USA
6.South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China

He, Leiyu,Xie, Lin,Wang, Dengjun,et al. Elucidating the Role of Sulfide on the Stability of Ferrihydrite Colloids under Anoxic Conditions[J]. ENVIRONMENTAL SCIENCE & TECHNOLOGY,2019,53(8):4173-4184.

He, Leiyu.,Xie, Lin.,Wang, Dengjun.,Li, Wenlu.,Fortner, John D..,...&Liu, Chongxuan.(2019).Elucidating the Role of Sulfide on the Stability of Ferrihydrite Colloids under Anoxic Conditions.ENVIRONMENTAL SCIENCE & TECHNOLOGY,53(8),4173-4184.

He, Leiyu,et al."Elucidating the Role of Sulfide on the Stability of Ferrihydrite Colloids under Anoxic Conditions".ENVIRONMENTAL SCIENCE & TECHNOLOGY 53.8(2019):4173-4184.