{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T07:01:58Z","timestamp":1790146918122,"version":"4.0.1"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T00:00:00Z","timestamp":1790121600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Chem."],"abstract":"<jats:p>\n                    Excessive fluoride (F\n                    <jats:sup>\u2212<\/jats:sup>\n                    ) in groundwater poses a serious threat to human health, necessitating the development of efficient defluorination materials. In this study, a novel composite hydrogel bead (La-SP\/SA) was fabricated by incorporating shale powder (SP) into sodium alginate (SA) matrix followed by crosslinking with lanthanum chloride. The synthesis conditions were determined as SP dosage 4.0%, La\n                    <jats:sup>3+<\/jats:sup>\n                    concentration 0.2\u00a0mol L\n                    <jats:sup>\u22121<\/jats:sup>\n                    , and crosslinking time 12\u00a0h. Under adsorbent dosage of 0.7\u00a0g L\n                    <jats:sup>\u22121<\/jats:sup>\n                    , initial F\n                    <jats:sup>\u2212<\/jats:sup>\n                    concentration of 9.0\u00a0mg L\n                    <jats:sup>\u22121<\/jats:sup>\n                    , and pH of 5.0, La-SP\/SA achieved an excellent removal efficiency of 94.33% (12.18\u00a0mg g\n                    <jats:sup>\u22121<\/jats:sup>\n                    ), with a residual F\n                    <jats:sup>\u2212<\/jats:sup>\n                    concentration meeting both the WHO guideline and Chinese standard. Kinetic analysis revealed that the adsorption process followed the pseudo-second-order model, characteristic of chemisorption-dominated systems. The composite hydrogel beads exhibited excellent selectivity toward F\n                    <jats:sup>\u2212<\/jats:sup>\n                    in the presence of coexisting anions (Cl\n                    <jats:sup>\u2212<\/jats:sup>\n                    , SO\n                    <jats:sub>4<\/jats:sub>\n                    <jats:sup>2\u2212<\/jats:sup>\n                    , HCO\n                    <jats:sub>3<\/jats:sub>\n                    <jats:sup>\u2212<\/jats:sup>\n                    , and NO\n                    <jats:sub>3<\/jats:sub>\n                    <jats:sup>\u2212<\/jats:sup>\n                    ) and maintained over 98.01% of initial adsorption capacity over 5\u00a0days across pH 4.0\u20139.0. Mechanistic investigations using SEM-EDS, FTIR, XRD, and XPS demonstrated that F\n                    <jats:sup>\u2212<\/jats:sup>\n                    removal occurred via a synergistic mechanism involving electrostatic interaction, ion exchange, inner-sphere complexation, chemical precipitation, and chemisorption. This work provides a promising strategy for fluoride-contaminated groundwater remediation while enabling the resource utilization of shale waste.\n                  <\/jats:p>","DOI":"10.3389\/fchem.2026.1962172","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T06:20:38Z","timestamp":1790144438000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Lanthanum-modified shale powder\/alginate composite hydrogel beads for fluoride-contaminated groundwater treatment"],"prefix":"10.3389","volume":"14","author":[{"given":"Sitong","family":"Liu","sequence":"first","affiliation":[{"name":"Academic Affairs Office, Kunming Railway Vocational and Technical College","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaoxiong","family":"Li","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xu","family":"Bi","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guangying","family":"Feng","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhao","family":"Wang","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiusheng","family":"Yuan","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yue","family":"Xu","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ningyi","family":"Li","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Science and Engineering, Kunming University of Science and Technology","place":["Kunming, Yunnan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,23]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"109215","DOI":"10.1016\/j.jwpe.2025.109215","article-title":"Biopolymer-encapsulated Al\/Tb-Layered double hydroxide hydrogel beads for efficient Cr(VI) removal: green synthesis, Box\u2013Behnken optimization, and comprehensive adsorption mechanism analysis","volume":"80","author":"Aljohani","year":"2025","journal-title":"J. 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