Removal　of　copper　ions　(Cu(II))　efficiently　from　water　is　crucial　for　water　environment　security.　We　use　sustainable,　low-cost,　renewable　cellulose　derivatives　(carboxymethylcellulose　sodium　(CMC-Na))　and　polyvinyl　alcohol　(PVA)　as　the　matrix,　and　cellulose　nanocrystals　(CNCs)　as　the　functional　addition.　The　CNC/CMC-Na/PVA　hydrogel　was　prepared　by　the　physical　cross-linking　method.　Static　adsorption　experiments　proved　that　CNC/CMC-Na/PVA　hydrogel　has　a　greater　adsorption　potential　(108 mg/g)　towards　Cu(II).　At　the　same　time,　the　adsorption　of　Cu(II)　on　CNC/CMC-Na/PVA　hydrogels　is　spontaneous　and　endothermic,　and　obeys　the　pseudo-second-order　model　with　intra-particle　diffusion.　Furthermore,　the　primary　adsorption　mechanisms　had　been　electrostatic　attraction　and　surface　complexation.　Importantly,　CNC/CMC-Na/PVA　hydrogel　has　efficient　absorbability　and　preferable　reusability　in　actual　water　samples.　Furthermore,　the　copper　nanoparticles　(Cu　NPs)　adsorbed　on　the　surface　of　CNC/CMC-Na/PVA　hydrogels　were　reduced　with　NaBH4　in　situ　to　realize　the　secondary　utilization　in　CNC/CMC-Na/PVA　hydrogels　supported　by　Cu　NPs.　It　is　found　that　the　material　can　be　used　as　a　catalyst　to　efficiently　catalyze　the　conversion　of　HMF　to　BHMF　(99%).　Consequently,　we　provide　insights　into　the　hydrogel　preparation　that　would　possibly　be　promising　novel　adsorbents　for　the　elimination　of　heavy-ion　from　sustainable　water　purification.　Graphical　abstract:　[Figure　not　available:　see　fulltext.]　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer　Nature　B.V.