{"688481":{"#nid":"688481","#data":{"type":"event","title":"PhD Defense by Chengchao Xiao","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003ESchool of Civil and Environmental Engineering\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EPh.D. Thesis Defense Announcement\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAdvanced Separation Technologies for Lithium-Ion Battery Recycling Using Cyanex 272\u2013Blended PVDF Composites from Membranes to Fixed-Bed Columns\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EBy Chengchao Xiao\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAdvisor:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDr. Yongsheng Chen\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee Members: Dr. Hailong Chen (MSE), Dr. Xing Xie (CEE),\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDr. Shane. A. Snyder (CEE), Dr. Joe F. Bozeman (CEE)\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDate and Time: March, 06, 2026. 10am EST\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ELocation: Daniel Lab 303\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESelective separation of Co(II) from Ni(II) in sulfate-based lithium-ion battery leachates remains a major bottleneck in hydrometallurgical recycling because these adjacent transition metals exhibit closely similar aqueous chemistries. This dissertation develops a scalable solid-phase extraction platform by physically immobilizing the organophosphorus extractant Cyanex 272 within a polyvinylidene fluoride (PVDF) polymer matrix and using morphological engineering to translate molecular coordination selectivity into process-relevant separation performance. The study progresses from planar PVDF\u2013Cyanex 272 adsorptive membranes to hierarchically porous beads fabricated via controlled non-solvent induced phase separation, and finally to continuous fixed-bed column operation to quantify how material structures govern dynamic selectivity and mass-transfer limitations. Planar membranes confirm\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003Ethat Cyanex 272 retains its intrinsic Co(II) preference upon immobilization, achieving Co(II)\/Ni(II) separation factors up to 209.5 at pH 6.8 and 75 \u00b0C, while also revealing a capacity ceiling (1.42 mg\u00b7g\u207b\u00b9) imposed by two-dimensional geometry and restricted extractant accessibility. Morphology-engineered beads overcome this limitation by creating interconnected transport pathways that improve internal site utilization, increasing cobalt capacity to 14.1 mg\u00b7g\u207b\u00b9. Under continuous flow, fixed-bed experiments exhibit pronounced Ni(II) roll-up, which indicates competitive chromatographic displacement by the higher-affinity Co(II) front. Breakthrough analysis indicates diffusion-limited saturation behavior, for which our Modified Yan model provides superior predictive performance across operating conditions (\ud835\udc79\ud835\udc79\u00b2 \u0026gt; 0.99) compared with idealized models such as Thomas. Process optimization identifies pH 6.15 as a practical set point balancing uptake kinetics and thermodynamic selectivity, and the system demonstrates robust reusability with regeneration efficiencies exceeding 97.8% over ten cycles using 0.5 M H\u2082SO\u2084. Overall, the dissertation establishes a mechanistically grounded, performance-intensified solid-phase route for Co(II)\/Ni(II) separation that bridges coordination chemistry, morphology, and fixed-bed process design for advanced battery recycling.\u003C\/strong\u003E\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAdvanced Separation Technologies for Lithium-Ion Battery Recycling Using Cyanex 272\u2013Blended PVDF Composites from Membranes to Fixed-Bed Columns\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Advanced Separation Technologies for Lithium-Ion Battery Recycling Using Cyanex 272\u2013Blended PVDF Composites from Membranes to Fixed-Bed Columns"}],"uid":"27707","created_gmt":"2026-02-23 19:29:54","changed_gmt":"2026-02-23 19:30:23","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2026-03-06T10:00:00-05:00","event_time_end":"2026-03-06T12:00:00-05:00","event_time_end_last":"2026-03-06T12:00:00-05:00","gmt_time_start":"2026-03-06 15:00:00","gmt_time_end":"2026-03-06 17:00:00","gmt_time_end_last":"2026-03-06 17:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Daniel Lab 303","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}