Montmorillonite-iron crosslinked alginate beads for aqueous phosphate removal
Montmorillonite-iron crosslinked alginate beads for aqueous phosphate removal
复制标题
DOI：
10.1016/j.chemosphere.2021.130837
复制
发表时间：
2021-05-17
期刊：
影响因子：
8.8
通讯作者：
Bezbaruah, Achintya N.
中科院分区：
文献类型：
--
作者：
Das, Tonoy K.;Scott, Quentin;Bezbaruah, Achintya N.
农田的磷酸盐径流导致水体富营养化，对水生生态系统造成破坏性影响。在这项研究中，合成了天然存在的蒙脱石粘土掺铁交联藻酸盐生物聚合物（MtIA）珠，并评估了其对水体磷酸盐的去除效果。批量实验数据显示，MtIA 珠可以从不同初始磷酸盐浓度（1 和 5 mg PO43--P/L，以及 100 μg PO43--P/L）的溶液中有效去除磷酸盐（>99%）。动力学数据很好地符合准二级动力学模型，表明化学吸附在磷酸盐去除中发挥着重要作用。根据对 Elovich 模型和颗粒内扩散模型结果的分析，发现 MtIA 珠去除磷酸盐是化学吸附，薄膜扩散和颗粒内扩散都参与其中。等温线研究表明，MtIA 表面是异质的，根据 Langmuir 模型计算出的珠子的吸附容量为 48.7 mg PO43-.P/g 干珠，这比其他粘土-金属-藻酸盐珠子报道的值高出 2.3 倍。珠子的电子显微镜 (SEM-EDS) 数据显示出粗糙的表面，这有助于珠子与磷酸根离子更好地接触。傅立叶变换红外光谱（FTIR）表明铁和蒙脱石粘土都参与了与藻酸盐链的交联。 MtIA 珠在 2-10 的广泛 pH 范围内有效工作（>98% 的磷酸盐去除率），使其成为一种强大的吸附剂。这些珠子可用于从富营养化湖泊、农业径流和城市废水中回收磷酸盐。
Phosphate runoff from agriculture fields leads to eutmphication of the water bodies with devastating effects on the aquatic ecosystem. In this study, naturally occurring montmorillonite clay-incorporated iron crosslinked alginate biopolymer (MtIA) beads were synthesized and evaluated for aqueous phosphate removal. Batch experiment data showed an efficient phosphate removal (>99%) by the MtIA beads from solutions with different initial phosphate concentrations (1 and 5 mg PO43--P/L, and 100 mu g PO43--P/L). The kinetic data fitted well into the pseudo-second-order kinetic model indicating chemisorption played an important role in phosphate removal. Based on analyses of results from the Elovich and intra-particulate diffusion models, phosphate removal by the MtIA beads was found to be chemisorption where both film diffusion and intra-particulate diffusion participated. The isotherm studies indicate that MtIA surfaces were heterogeneous, and the adsorption capacity of the beads calculated from Langmuir model was 48.7 mg PO43-.P/g of dry beads which is similar to 2.3 times higher than values reported for other clay-metal-alginate beads. Electron microscopy (SEM-EDS) data from the beads showed a rough-textured surface which helped the beads achieve better contact with the phosphate ions. Fourier-transform infrared spectroscopy (FTIR) indicated that both iron and montmorillonite clay participated in crosslinking with the alginate chain. The MtIA beads worked effectively (>98% phosphate removal) over a wide pH range of 2-10 making it a robust adsorbent. The beads can potentially be used for phosphate recovery from eutrophic lakes, agricultural run-off, and municipal wastewater.