Calcium silicate hydrate complex konjac glucomannan-based hydrogel selectively adsorbed phosphate in low alkalinity
Xingyu Wu1, Siyu Liu1, Siqi Song1
1College of Environment Sciences, Sichuan Agricultural University, Chengdu, 611130, China.
Journal of Environmental Management
|September 19, 2024
Summary
A new composite hydrogel efficiently recovers phosphate from wastewater, acting as a potential slow-release fertilizer. This material shows high adsorption capacity and selectivity, even in complex solutions like biogas slurry.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Nutrient management in wastewater is crucial for environmental protection.
- Phosphorus recycling from wastewater conserves valuable resources.
- Existing methods for phosphate recovery face challenges in efficiency and selectivity.
Purpose of the Study:
- To develop a novel composite hydrogel for efficient phosphate recovery from aqueous solutions.
- To investigate the adsorption capacity, kinetics, and selectivity of the developed material.
- To explore the potential application of the recovered phosphate and the adsorbent.
Main Methods:
- Synthesis of konjac glucomannan/pectin/calcium silicate composite hydrogel (KP-CSH).
- Phosphate adsorption experiments under various pH conditions and concentrations.
- Kinetic and isotherm studies to determine adsorption mechanisms.
- Selectivity tests in the presence of competing ions and in real biogas slurry.
- Analysis of adsorption sites and mechanisms (ligand exchange, complexation).
- Plant seed germination and seedling growth tests.
Main Results:
- KP-CSH demonstrated high phosphate adsorption capacity (39–45 mg-P/g in a wide pH range, max 61.2 mg-P/g).
- The adsorption process was identified as chemical adsorption, primarily involving calcium sites.
- KP-CSH showed excellent selectivity for phosphate over other ions in complex matrices.
- The hydrogel maintained effectiveness even at near-neutral pH after adsorption.
- Post-recovery KP-CSH did not negatively impact plant growth and increased chlorophyll content.
Conclusions:
- KP-CSH is a highly effective and selective adsorbent for phosphate recovery from wastewater.
- The material's mechanism involves ligand exchange and intra-sphere complexation.
- KP-CSH shows promise for resource recovery and potential use as a slow-release phosphate fertilizer.
Keywords:
AlkalescenceBio-based hydrogelCalcium silicate hydrateSelective adsorptionSoilless cultivation mediumMore Related Videos
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