The　rapid,　efficient,　and　convenient　removal　of　hazardous　radionuclides　137Cs　and　90Sr　is　an　urgent　need　in　the　remediation　of　environmental　radioactive　contamination.　Herein,　a　biomass　composite　membrane　of　K2xSn4−xS8−x/collagen　fibers　(KTS-3/CFs)　was　obtained　by　successfully　loading　the　metal　sulfide　ion　exchanger　of　K2xSn4−xS8−x　(KTS-3)　on　CFs　through　the　principle　of　fiber　papermaking.　The　membrane　is　characterized　by　a　homogeneous　shape,　operability,　good　water　stability,　and　easy　degradation.　It　exhibits　satisfactory　capability　for　removing　Cs+　and　Sr2+　ions,　achieving　maximum　adsorption　capacities　of　82.34　mg/g　for　Cs+　and　32.98　mg/g　for　Sr2+,　respectively.　Meanwhile,　the　KTS-3/CFs　membrane　has　fast　kinetic　performance　and　a　wide　pH　activity　range　for　removing　Cs+　and　Sr2+　ions.　Further,　it　can　still　efficiently　capture　Cs+　and　Sr2+　ions　under　the　coexistence　of　K+,　Na+,　Ca2+,　and　Mg2+　ions,　and　even　in　actual　water　samples.　The　removal　of　Cs+　and　Sr2+　ions　by　the　KTS-3/CFs　is　mainly　attributed　to　the　ion　exchange　of　Cs+　and　Sr2+　with　K+　in　the　interlayer　spaces　of　KTS-3,　while　the　CFs　act　as　the　support　material　for　the　formation　of　the　membrane.　Moreover,　the　KTS-3/CFs　composite　membrane　is　also　capable　of　the　fast　and　efficient　capture　of　Cs+　and　Sr2+　ions　in　a　continuous　filtration　manner.　This　work　not　only　develops　an　environmentally　friendly,　convenient,　and　accessible　method　for　the　preparation　of　metal　sulfide　composites　but　also　paves　the　way　for　the　development　of　new　high-efficiency　composite　materials　for　radionuclides　remediation.　©　Science　China　Press　2025.