One-pot preparation of amphoteric cellulose polymers for simultaneous recovery of ammonium and dihydrogen phosphate from wastewater and reutilizing as slow-release fertilizer

•A simple approach to prepare EAC via one-pot reaction system was proposed.•The adsorption capacity of EAC for NH4+ and H2PO4- was 40.38 and 30.42 mg/g, respectively.•The adsorption of EAC to NH4+ and H2PO4- fitted second-order and Langmuir models well.•The NH4+ and H2PO4- laden adsorbents exhibited preferable slow-release behavior.