Insights into cadmium adsorption characteristics and mechanisms by new granular alginate hydrogels reinforced with biochar: Important role of cation exchange

被引：0

作者：

Ben Salem, Dhirar ^{[1
]}

Yahiaoui, Khemissi ^{[2
]}

Bernardo, Maria ^{[3
]}

Gatica, Jose Manuel ^{[4
,5
]}

Ouakouak, Abdelkader ^{[2
]}

Touahra, Fouzia ^{[6
]}

Eltaweil, Abdelazeem Saad ^{[7
]}

Tran, Hai Nguyen ^{[8
,9
]}

机构：

[1] Univ Biskra, Res Lab Subterranean & Surface Hydraul, POB 145, Biskra 07000, Algeria

[2] Univ El Oued, Hydraul & Civil Engn Dept, POB 789, El Oued 39000, Algeria

[3] NOVA Univ Lisbon, NOVA Sch Sci & Technol, LAQV, REQUIMTE, P-2829516 Caparica, Portugal

[4] Univ Cadiz, Dept Ciencia Mat & Ingn Metalurg & Quim Inorgan, Puerto Real 11510, Spain

[5] Univ Cadiz, Inst Microscopia Elect & Mat IMEYMAT, Puerto Real 11510, Spain

[6] Ctr Rech Sci & Tech Anal Phys Chim CRAPC, Zone Ind,BP 384, Bouismail, Tipasa, Algeria

[7] Alexandria Univ, Fac Sci, Chem Dept, Alexandria, Egypt

[8] Duy Tan Univ, Inst Fundamental & Appl Sci, Ctr Energy & Environm Mat, Ho Chi Minh City 700000, Vietnam

[9] Duy Tan Univ, Fac Environm & Chem Engn, Da Nang City 50000, Vietnam

来源：

JOURNAL OF ENVIRONMENTAL MANAGEMENT | 2025年 / 383卷

关键词：

Cation exchange; Biochar; Hydrogel; Heavy metal; Surface complexation; Water treatment; SORPTION MECHANISMS; SODIUM ALGINATE; BEADS; WATER; IONS; SELECTIVITY; FABRICATION; REMOVAL; PB(II); CARBON;

D O I：

10.1016/j.jenvman.2025.125407

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Green biochar-alginate composite (BAB) was synthesized by integrating biochar derived from peanut shells (PS700) with Na-alginate using a Ca2+ cross-linker. A hydrogel bead (SAB) was prepared using sodium alginate without biochar. The materials were characterized by the SEM-EDS, XRD, FTIR, XPS, TGA-DTG, and BETanalyzer techniques. They were applied as adsorbents to adsorb Cd2+ ions from aqueous solutions in batch adsorption experiments. XRD data confirmed that BAB exhibited a crystalline structure, with 2 theta peaks corresponding to PS700 (similar to 24 degrees and 42 degrees) and SAB (similar to 13 degrees). SEM images suggested PS700 was successfully encapsulated within alginate beads. BAB microsphere had a large specific surface area (353.2 m(2)/g) and dominant micropore (1.86 nm). Adsorption results indicated the Langmuir maximum adsorption capacities of BAB, SAB, and PS700 were 230.0, 125.6, and 92.3 mg/g. Cation exchange was a primary Cd adsorption mechanism by BAB that was determined by a qualitative study (%Ca decreasing from 2.43% to 1.27% after adsorption) and a quantitative experiment (cation exchange ratio between Ca exchange and Cd adsorption: q(exchanged)/q(e) = 0.7). The XPS spectrum for C 1s (binding energy peak at similar to 282 eV) and Ca 2p (similar to 348 eV) highlighted that Ca in the Ca-C bond of BAB was remarkably replaced by Cd ions in solution to form the Cd-C bond in the Cd-laden BAB. The O 1s spectrum (peak at similar to 532 eV) demonstrated the presence of surface complexation and electron-sharing phenomenon between the ionized carboxyl groups in BAB and Cd. Cd-pi interaction was observed at 405.96 eV in the Cd 3d spectrum. Pore filling and van der Waals force played a minor role in adsorption mechanisms. The calculated costs (10(-3) US$/g) for adsorbing 1 g of cadmium per the maximum adsorption capacity of PS700, SAB, and BAB were 2.69, 18.79-129.8, and 5.72-36.4, respectively. The innovative biochar-reinforced hydrogel beads can be an effective and green material for water treatment.

引用

页数：14