A sustainable biosorbent, silver nanoparticles-decorated coffee-ground waste (CWAg), was synthesized through a simple in-situ reduction method. CWAg is extensively characterized via SEM-EDX, PZC, FTIR, XRD, HR-TEM, and XPS analyses. The biosorbent was tested to remove chromium (Cr(VI)) and methylene blue (MB) from wastewater, and its antibacterial properties was evaluated. CWAg demonstrated efficient sorption efficiencies, achieving ⁓149.9 mg/g at 323 K and pH: 2.0 for Cr(VI) and ⁓113.4 mg/g at 293 K and pH: 6.0 for MB, at a biosorbent dose of 1 g/L. The equilibration times were 90 and 120 min for Cr(VI) and MB, with half-sorption times (t