scholarly journals Influence of sulfide, chloride and dissolved organic matter on mercury adsorption by activated carbon in aqueous system

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Chi Chen ◽  
Yu Ting ◽  
Boon-Lek Ch’ng ◽  
Hsing-Cheng Hsi
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Dissolved Organic Matter ◽  
Operational Definition ◽  
Aqueous System ◽  
Contaminated Sediment ◽  
Batch Experiments ◽  
Adsorption Performance ◽  
Negative Effect ◽  
Pseudo Second Order

Abstract Using activated carbon (AC) as thin layer capping to reduce mercury (Hg) released from contaminated sediment is a feasible and durable remediation approach. However, several aqueous factors could greatly affect the Hg fate in the aquatic system. This study thus intends to clarify the influences on Hg adsorption by AC with the presence of sulfide, dissolved organic matter (DOM), and chloride. The lab-scale batch experiments were divided into two parts, including understanding (1) AC adsorption performance and (2) Hg distribution in different phases by operational definition method. Results showed that the Hg adsorption rate by AC was various with the presence of sulfide, chloride, and DOM (from fast to slow). Hg adsorption might be directly bonded to AC with Hg-Cl and Hg-DOM complexes and the rate was mainly controlled by intraparticle diffusion. In contrast, “Hg + sulfide” result was better described by pseudo-second order kinetics. The Hg removal efficiency was 92–95% with the presence of 0–400 mM chloride and approximately 65–75% in the “Hg + sulfide” condition. Among the removed Hg, 24–29% was formed into aqueous-phase particles and about 30% Hg was adsorbed on AC with 2–20 μM sulfide. Increasing DOM concentration resulted in more dissolved Hg. The proportion of dissolved Hg increased 31% by increasing DOM concentration from 0.25 to 20 mg C L− 1. Simultaneously, the proportion of adsorbed Hg by AC decreased by 47%. Overall, the presence of chloride increases the Hg adsorption by AC. In contrast, the presence of sulfide and DOM causes a negative effect on AC adsorption.

Characterization and Source of Trihalomethane Formation in the Secondary Effluent by Sequencing Batch Reactors

2013 ◽  
Vol 316-317 ◽  
pp. 323-326
Author(s):  
Chao Jie Zhang ◽  
Si Bo Li ◽  
Qian Chen ◽  
Qi Zhou
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Dissolved Organic Matter ◽  
Secondary Effluent ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Human Beings ◽  
By Products

Dissolved organic matter (DOM) may do harms to human beings. After disinfected by chlorine (amine), DOM can form disinfection by-products (DBPs) which can be mutagenic, teratogenic and carcinogenic. Characterization and source of trihalomethane precursors in the secondary effluent by sequencing batch reactors were investigated. CHCl3 was the primary DBPs. The results showed that the precursors of CHCl3 were mainly strongly hydrophobic DOM, while CHCl2Br and CHClBr2 were mainly formed from hydrophilic DOM. The effects of different powder media (activated carbon, zeolite) on removal of DOM were compared. The results showed that the dosing of powder media can promote the removal of DOM and the DBPs precursors.

scholarly journals Adsorption of Nitrate onto ZnCl2-Modified Coconut Granular Activated Carbon: Kinetics, Characteristics, and Adsorption Dynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lingjie Liu ◽  
Min Ji ◽  
Fen Wang
Keyword(s):  
Activated Carbon ◽  
Granular Activated Carbon ◽  
Kinetic Studies ◽  
Surface Characteristics ◽  
Electrostatic Attraction ◽  
Batch Adsorption ◽  
Dynamic Adsorption ◽  
Batch Experiments ◽  
Nitrate Adsorption ◽  
Pseudo Second Order

Coconut granular activated carbon (CGAC) was modified by impregnating with ZnCl2solution to remove nitrate from aqueous solutions. Sorption isotherm and kinetic studies were carried out in a series of batch experiments. Nitrate adsorption of both ZnCl2-modified CGAC and CGAC fitted the Langmuir and Freundlich models. Batch adsorption isotherms indicated that the maximum adsorption capacities of ZnCl2-modified CGAC and CGAC were calculated as 14.01 mgN·g−1and 0.28 mgN·g−1, respectively. The kinetic data obtained from batch experiments were well described by pseudo-second-order model. The column study was used to analyze the dynamic adsorption process. The highest bed adsorption capacity of 1.76 mgN·g−1was obtained by 50 mgN·L−1inlet nitrate concentration, 20 g adsorbents, and 10 ml·min−1flow rate. The dynamic adsorption data were fitted well to the Thomas and Yoon–Nelson models with coefficients of correlationR2 > 0.834 at different conditions. Surface characteristics and pore structures of CGAC and ZnCl2-modified CGAC were performed by SEM and EDAX and BET and indicated that ZnCl2had adhered to the surface of GAC after modified. Zeta potential, Raman spectra, and FTIR suggested the electrostatic attraction between the nitrate ions and positive charge. The results revealed that the mechanism of adsorption nitrate mainly depended on electrostatic attraction almost without any chemical interactions.

scholarly journals Mobilisation of Al, Fe, and DOM from topsoil during simulated early Podzol development and subsequent DOM adsorption on model minerals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnes Krettek ◽  
Thilo Rennert
Keyword(s):  
Organic Matter ◽  
Acetic Acid ◽  
Dissolved Organic Matter ◽  
Flow Velocity ◽  
Heavy Rain ◽  
Oxide Phase ◽  
Batch Experiments ◽  
Important Species ◽  
Velocity Characteristic ◽  
Soil Percolation

AbstractPodzols are characterised by mobilisation of metals, particularly Al and Fe, and dissolved organic matter (DOM) in topsoil horizons, and by immobilisation in subsoil horizons. We mimicked element mobilisation during early podzolisation by irrigating the AE horizon of a Dystric Arenosol with acetic acid at different flow velocities and applying flow interruptions to study rate-limited release in experiments with soil cylinders. We used eluates in batch experiments with goethite and Al-saturated montmorillonite to investigate DOM reactivity towards minerals. Both the flow velocity and flow interruptions affected element release, pointing to chemical non-equilibrium of release and to particles, containing Fe and OM mobilised at larger flow velocity, characteristic of heavy rain or snowmelt. Based on chemical extractions, the source of mobilised Al and Fe, the vast majority of which was complexed by DOM, was no oxide phase, but rather organic. Rate limitation also affected the composition of DOM released. Carboxyl and phenolic species were the most important species adsorbed by both minerals. However, DOM composition affected the extent of DOM adsorption on goethite more distinctly than that on montmorillonite. Our findings evidence that the intensity of soil percolation affects quantitative and qualitative element release during early podzolisation and adsorptive DOM retention in subsoil horizons.

Bioturbation and Dissolved Organic Matter Enhance Contaminant Fluxes from Sediment Treated with Powdered and Granular Activated Carbon

2013 ◽  
Vol 47 (10) ◽  
pp. 5092-5100 ◽  
Author(s):  
D. Kupryianchyk ◽  
A. Noori ◽  
M. I. Rakowska ◽  
J. T. C. Grotenhuis ◽  
A. A. Koelmans
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Dissolved Organic Matter ◽  
Granular Activated Carbon

scholarly journals Biological factors of water quality in a mesotrophic ecosystem

Fisheries ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. 16-19
Author(s):  
Anatoliy Sadchikov ◽  
Sergei Ostroumov
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Aquatic Environment ◽  
Aquatic Ecosystems ◽  
Biological Factors ◽  
Physiological Processes ◽  
Negative Effect

Dissolved organic matter (DOM) is one of the important parameters of water quality in aquatic ecosystems. In the experiments, phyto- and bacterioplankton actively consumed 14C-labeled chlorella hydrolyzate. Removal (by filtration) of cyanobacteria from the aquatic environment leads to an increase in the rate of DOM consumption by bacteria. This indicates the possibility of a negative effect of cyanobacterial metabolites on the physiological processes of bacterioplankton.

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