Nature-based solutions for wastewater treatment: Biodegradable freeze-dried powdered bio-flocculant

作者：Sanja Cojbasic, Maja Turk Sekulić, Sabolč Pap, Mark A. Taggart, Jelena Prodanović · 发表于：Journal of Water Process Engineering · 年份：2024 · DOI：10.1016/j.jwpe.2024.105863 · 被引用次数：12 · 研究领域：Coagulation and Flocculation Studies、Freezing and Crystallization Processes、Microencapsulation and Drying Processes

A significant problem concerning the utilisation of nature-based coagulants (or biocoagulants) in practice and for commercialisation, is their stability (i.e., of their active components) and durability over long periods. In this context, a powdered biocoagulant was produced from common bean seeds (Phaseolus vulgaris) by extraction and freeze-drying and then tested for its stability and durability. Four powdered biocoagulants were tested and compared in terms of their coagulation activity, hygroscopicity, water solubility and moisture content. All 4 maintained high efficiency for turbidity removal (50.6–80.2 %) despite and during several months of storage (in both controlled and non-controlled conditions). Similarly, these biocoagulants had low hygroscopicity (between 7.6 and 8.5 g of water per 100 g of sample), moisture content (< 8 g per 100 g of sample) and high water solubility indices (between 88.0 and 92.7 % and between 62.6 and 78.1 % for salt and distilled water extracts, respectively) with a low coefficient of variation (< 5 %) during the testing period and within repeated experiments. Biocoagulants extracted with 0.5 M salt solution showed better results in terms of their tested physico-chemical properties. However, biocoagulants extracted by ultrasound extraction using distilled water as a solvent showed the highest consistency in terms of optimal coagulant dosage and achieved turbidity removal. Instrumental characterisation through SEM/EDX, FTIR, XRD and XPS analy...