Insights into the phosphate adsorption behavior onto 3D self-assembled cellulose/graphene hybrid nanomaterials embedded with bimetallic hydroxides

Lei Zhang; Zihang Wang; Xing Xu; Cheng Chen; Baoyu Gao; Xiaolong Xiao

doi:10.1016/j.scitotenv.2018.11.030

Insights into the phosphate adsorption behavior onto 3D self-assembled cellulose/graphene hybrid nanomaterials embedded with bimetallic hydroxides

Sci Total Environ. 2019 Feb 25:653:897-907. doi: 10.1016/j.scitotenv.2018.11.030. Epub 2018 Nov 4.

Authors

Lei Zhang¹, Zihang Wang², Xing Xu³, Cheng Chen², Baoyu Gao², Xiaolong Xiao⁴

Affiliations

¹ Shandong Provincial Key Laboratory of Oilfield Produced Water Treatment and Environmental Pollution Control, Sinopec Petroleum Engineering Corporation, PR China.
² Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
³ Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China. Electronic address: xuxing@sdu.edu.cn.
⁴ Shandong Provincial Key Laboratory of Oilfield Produced Water Treatment and Environmental Pollution Control, Sinopec Petroleum Engineering Corporation, PR China. Electronic address: dyxxl@126.com.

PMID: 30759615
DOI: 10.1016/j.scitotenv.2018.11.030

Abstract

3D self-assembled cellulose/graphene hybrids (3D cell/GO hybrids) were used as the host for encapsulating the Zr and La hydroxides, forming the Zr/La-cell/GO hybrids. After phosphate adsorption, the crystallization peaks of LaPO₄·xH₂O in saturated Zr/La-cell/GO hybrids were observed and they were reduced with the increase in pHs. Especially, a low crystallization was observed at pH 10.0 as compared with those at pH 3.0 and 6.0; this also corresponded well to the varied adsorption capacity as a function of pHs. The increased humic acid (HA) amounts (150 mg/L) only resulted in a low capacity loss (16.3%) in phosphate uptake from 25.3 to 21.2 mg/g. A noticeable La leach (2.1 mg/L) was observed at the HA level of 150 mg/L but no Zr leach was detected, and therefore, complexation of La with HA seemed a potential explanation for the increased La leaching. The interference of different coexisting anions on phosphate uptake followed the order as F^- > SiO₃^2- > HCO₃^- > SO₄^2- > NO₃^- > Cl^-. Phosphate uptake by Zr/La-cell/GO hybrids was significantly reduced at the co-existing fluoride partially due to the stronger electro-negativity of fluoride to combine with the protonated Zr/La hydroxides. In addition, Ca²⁺ laden on the Zr/La-cell/GO hybrids significantly enhanced the adsorption of phosphate by Zr/La-cell/GG hybrids due to the formation of calcium phosphate precipitation in framework of Zr/La-cell/GG hybrids.

Keywords: Bimetallic hydroxides; Cellulose; Graphene; Humic acid; Phosphate.