Porous 3D-Biocomposite Adsorbent for Iron Reclamation and Use in Agricultural Applications

Abstract

The essential nutrients (e.g., iron) for food production are nonrenewable resources, which cannot satisfy the need of a fast-growing global population. Meanwhile, excessive irons accumulated in iron-rich water pose an adverse effect on human and ecosystem health. Thus, it is necessary to develop a cost-effective and eco-friendly adsorbent for reclaiming irons from iron-accumulated water and which cannot satisfy the need of a fast-growing global population. Meanwhile, excessive irons accumulated in iron-rich water pose an adverse effect on human and ecosystem health. Thus, it is necessary to develop a cost-effective and eco-friendly adsorbent for reclaiming irons from iron-accumulated water and these irons for growing crops. In this study, a simple gelation–solidification process aided by phase separation is developed to fabricate a biodegradable alginate/polyvinyl alcohol/lignosulfonate (SA/PVA/LS) three-dimensional (3D) biocomposite adsorbent. Calcium chloride and boric acid are used as cross-linkers between polymers with hydroxyl groups. This bioadsorbent owns a multiporous architecture, ample functional groups, and enhanced total pore volume. A multilayer adsorption mechanism endows it with a high iron adsorption capacity (52 mg/g) via Langmuir simulation and a physiochemical adsorption mechanism. The porous 3D structure of the biocomposite could be observed from SEM and CT scanning. After iron loading, it can be applied as an excellent substitute for a commercial EDTA-Fe micronutrient to promote plant growth with a comparable ratio of root to shoot length. This eco-friendly, highly efficient, and filled 3D bioadsorbent is expected to open a door to achieving circular recovery of plant essential plant nutrients from waste resources for crop production.