As　a　solid　hazardous　waste　material,　economical　and　environmental　efficacy　of　spent　adsorbent　loaded　by　toxic　heavy　metals　(HMs)　are　often　neglected,　which　maybe　bring　serious　secondary　pollution.　In　this　work,　we　report　a　green　recycle　route　for　spent　HM-bearing　calcium　silicate　hydrate　(CSH)　adsorbents　to　construct　nanocrystal-loaded　functional　materials.　Typically,　bimetallic　CuNi　catalyst　(Cu-Ni@deCa-CSH)　is　obtained　by　CO2　weathering　decalcification　of　the　exhausted　CSH　adsorbed　by　Cu2+　and　Ni2+,　and　subsequently　reducing　at　550　℃　for　6　h　under　5　vol%　H2/Ar.　The　universal　precursor,　HM　loaded　CSH　spent　adsorbents,　could　be　ideal　for　implementing　‘CO2　decalcification-H2　reduction’　to　obtain　more　metal　or　metal　oxide　nanoparticle　loaded　deCa-CSH　samples　(Cu-Fe@deCa-CSH,　Cu-ZnO@deCa-CSH,　Cu-CoO@deCa-CSH,　Cu-CeO2@deCa-CSH,　etc.),　which　can　dramatically　change　the　surface　acidity　of　substrate　owing　to　the　phase　transformation　from　basic　CSH　to　inert　silica　(deCa-CSH),　thus　benefitting　catalytic　reactions.　As　a　case　study,　the　typical　100Cu-100Ni@deCa-CSH　(The　initial　ion　concentration　is　100　mg/L)　exhibits　good　catalytic　activity　and　stability　for　p-nitrophenol　(p-NP)　hydrogenation　into　p-aminophenol　(p-AP)　with　NaBH4　reducing　agent.　The　conversion　efficiency　of　99.04%　can　be　achieved　within　18　min　(initial　p-NP:　60　mL,　20　mg/L,　Catalyst:　20　mg,　NaBH4:　40　mg,　pH　=　8).　Ni　addition　facilitates　electron　transfer　from　Ni　to　Cu,　and　the　resultant　lower　electron　binding　restraint　in　the　heterostructure　thus　improves　the　conversion　efficiency　of　p-NP.　Important　parameters　(p-NP　initial　concentration,　NaBH4　addition　dosage,　solution　pH,　etc.)　are　discussed　extensively　to　understand　how　to　prefer　reaction　conditions　for　p-NP　hydrogenation.　The　developed　surface　chemistry　strategy　thus　provides　a　realistic　basis　for　the　formation　of　functional　materials　via　explore　the　potential　value　of　solids　post-use.　©　2024　Elsevier　B.V.