Urea formaldehyde modified alginate beads with improved stability and enhanced removal of Pb2+, Cd2+, and Cu2

Ping Qu; Yuncong Li; Hongying Huang; Jianjun Chen; Zebin Yu; Jun Huang; Hailong Wang; Bin Gao

doi:10.1016/j.jhazmat.2020.122664

Urea formaldehyde modified alginate beads with improved stability and enhanced removal of Pb²⁺, Cd²⁺, and Cu²

J Hazard Mater. 2020 Sep 5:396:122664. doi: 10.1016/j.jhazmat.2020.122664. Epub 2020 Apr 16.

Authors

Ping Qu¹, Yuncong Li², Hongying Huang³, Jianjun Chen⁴, Zebin Yu⁵, Jun Huang⁶, Hailong Wang⁷, Bin Gao⁸

Affiliations

¹ Recycling Agriculture Research Center, Jiangsu Academy of Agricultural Sciences, Key laboratory of Crop and livestock Integrated Farming, Ministry of Agriculture, Nanjing, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, Jiangsu Province, 210014, China; Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32606, USA; Soil and Water Science Department, Tropical Research and Education Center, University of Florida, Homestead, FL, 33031, USA.
² Soil and Water Science Department, Tropical Research and Education Center, University of Florida, Homestead, FL, 33031, USA.
³ Recycling Agriculture Research Center, Jiangsu Academy of Agricultural Sciences, Key laboratory of Crop and livestock Integrated Farming, Ministry of Agriculture, Nanjing, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, Jiangsu Province, 210014, China.
⁴ Mid-Florida Research & Education Center, University of Florida, Apopka, FL, 32703, USA.
⁵ School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China.
⁶ Hualan Design & Consulting Group Co. Ltd., Nanning, 530011, China; College of Civil Engineering and Architecture Guangxi University, Nanning, 530004, China.
⁷ School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong, 528000, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China.
⁸ Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32606, USA. Electronic address: bg55@ufl.edu.

PMID: 32339875
DOI: 10.1016/j.jhazmat.2020.122664

Abstract

Urea formaldehyde (UF) was grafted onto the backbone of alginate to prepare microbeads as an adsorbent for the removal of heavy metal ions from aqueous solutions. The expensive alginate was crosslinked with cheaper UF at different ratios (1: 2.5∼1: 12.5) to produce sturdy alginate-UF beads at lower cost. Characterization results showed that UF modification enhanced the pore network and structural stability of the beads, which can be attributed to the reduced intermolecular forces and plentiful of nitrogen and oxygen donor atoms of the beads. The swelling of air-dried alginate-UF beads in different solutions was much lower than that of the unmodified alginate beads, confirming the improved stability. The replacement of alginate with UF at different ratios either did not affect or increased the adsorption of heavy metal ions (Pb²⁺, Cd²⁺, and Cu²⁺) on the beads. For example, the adsorption capacities of Pb²⁺, Cd²⁺, and Cu²⁺ on air-dried alginate-UF (1: 2.5) beads were 1.66, 0.61, and 0.80 mmol/g, which were 39.88%, 9.29%, and 9.52% higher than those of the corresponding unmodified alginate beads, respectively. The adsorption of heavy metals on the alginate-UF beads was mainly controlled by ion exchange, complexation, and electrostatic interaction mechanisms.

Keywords: Cd(II); Cu(II); Pb(II); Sodium alginate; adsorption mechanisms.

Publication types

Research Support, Non-U.S. Gov't