title: A new, low-cost adsorbent: preparation, characterization, and adsorption behavior of Pb(II) and Cu(II).
abstract: This work aimed to develop waste (i.e., sulfonated lignin) application in simulated wastewater treatment. Sulfonated lignin (LS), a byproduct of the paper industry, was intercalated into a parent host of layered double hydroxides (LDH) by swelling-restacking method. X-ray diffraction patterns of the composite confirmed that long-chain LS anions exited in the interlayer of Mg2Al-LDH in two forms: (1) a "flat" form with d003=0.88 nm; and (2) a "vertical" form with d003=9.08 nm. Results showed that the obtained Mg2Al-LS-LDH composite was highly selective and efficient for the removal of Pb(2+) and Cu(2+), especially Pb(2+), compared with the NO3-LDH precursor. The coexisting cations decreased the removal efficiency of Pb(2+) or Cu(2+) on Mg2Al-LS-LDH composite, which could be ascribed to outer-sphere sorption style, and the effect order of cations is Li(+)>Ca(2+)>K(+)>Na(+). The pseudo-second-order model appropriately described the sorption kinetics of Mg2Al-LS-LDH composite for Pb(2+) and Cu(2+). Sorption isotherms for Pb(2+) and Cu(2+) by the Mg2Al-LS-LDH composite were found to be more satisfactorily fitted by the Langmuir model than by the Freundlich one. With increased Pb(2+) or Cu(2+) concentration from 2 ppm to 200 ppm, the maximum absorption capacity of the composite toward Pb(2+) was ∼123 mg/g and that toward Cu(2+) was ∼64 mg/g. Therefore, a new, low-cost adsorbent was synthesized by utilizing the byproduct LS, which may be a potential remedy for Pb(2+) or Cu(2+) in contaminated water.
authors.affiliation: School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China. Electronic address: glhuang99@126.com.
authors.forename: Gailing
authors.initials: G
authors.lastname: Huang
authors.affiliation: School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, China. Electronic address: mashulan@bnu.edu.cn.
authors.forename: Shulan
authors.initials: S
authors.lastname: Ma
authors.affiliation: School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Chen
authors.affiliation: School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.affiliation: School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
authors.forename: Peiyuan
authors.initials: P
authors.lastname: Wang
keywords: Adsorption mechanism; Layered double hydroxides; Removal of lead(II) and copper(II); Selective adsorption; Sulfonated lignin