Yang, Ting and Hodson, Mark Edward orcid.org/0000-0002-8166-1526 (2018) Investigating the potential of synthetic humic-like acid to remove metal ions from contaminated water. Science of the Total Environment. pp. 1036-1046. ISSN 0048-9697
Abstract
Humic acid can effectively bind metals and is a promising adsorbent for remediation technologies. Our studies initially focussed on Cu2+ as a common aqueous contaminant. Previous studies indicate that carboxylic groups dominate Cu2+ binding to humic acid. We prepared a synthetic humic-like acid (SHLA) with a high COOH content using catechol (0.25M) and glycine (0.25M) with a MnO2 catalyst (2.5% w/v) at pH = 8 and 25 C and investigated the adsorption behaviour of Cu2+ onto it. The SHLA exhibited a range of adsorption efficiencies (27% - 99%) for Cu2+ depending on reaction conditions. A pseudo-second-order kinetic model provided the best fit to the experimental data (R2 = 0.9995-0.9999, p < 0.0001), indicating that chemisorption was most likely the rate-limiting step for adsorption. The equilibrium adsorption data showed good fits to both the Langmuir (R2 = 0.9928 – 0.9982, p < 0.0001) and Freundlich (R2 = 0.9497 – 0.9667, p < 0.0001) models. The maximum adsorption capacity (qm) of SHLA increased from 46.44 mg/g to 58.78 mg/g with increasing temperature from 25 C to 45 C. Thermodynamic parameters (ΔG0=2.50-3.69 kJ/mol; ΔS0=0.06 kJ/(mol·K); ΔH0=15.23 kJ/mol) and values of RL (0.0142-0.3711) and n (3.264-3.527) show that the adsorption of Cu2+ onto SHLA was favourable, spontaneous and endothermic in nature. Over six adsorption/desorption cycles using 0.5M HCl for the desorption phase, there was a 10% decrease of the adsorption capacity. A final experiment using a multi-metal solution indicated adsorption efficiencies of up to 84.3-98.3% for Cu, 86.6-98.8% for Pb, 30.4-82.9% for Cr, 13.8-77.4% for Ni, 9.2-62.3% for Cd, 8.6-51.9% for Zn and 4.6-42.1% for Co. Overall, SHLA shows great potential as an adsorbent to remove metals from water and wastewater.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Elsevier B.V. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. |
Keywords: | Synthetic humic-like acid,metal ions,adsorption,kinetics,curves,thermodynamics |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Environment and Geography (York) |
Depositing User: | Pure (York) |
Date Deposited: | 23 Apr 2018 15:40 |
Last Modified: | 02 Apr 2025 23:12 |
Published Version: | https://doi.org/10.1016/j.scitotenv.2018.04.176 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1016/j.scitotenv.2018.04.176 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:129955 |
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