Heavy metal contamination stemming from industrial waste is an increasingly grave issue with extensive repercussions for human health and ecological environment. Biochar has been demonstrated to have significant potential in the remediation of heavy metal pollution. However, the effectiveness of raw biochar is constrained under conditions of low pH and high heavy metal concentrations. In order to address this challenge effectively, this study utilized dragon fruit peels as precursors to prepare biochar via pyrolysis at 500 °C for 2 hours. The development of an efficient green adsorbent termed GBMSs (green biochar-metakaolin-sodium silicate) has been accomplished. Response surface methodology (RSM) tests revealed that GBMSs exhibited exceptional adsorption performance for zinc, achieving up to 67.37 mg/L at pH=2. Kinetic and isothermal adsorption studies indicated that adsorption of Cu and Zn onto GBMSs closely followed the Langmuir model and the pseudo-second-order kinetic equation, suggesting homogeneous monolayer surface adsorption with a rapid adsorption rate, and the adsorption capacity increased with rising pH. In-depth analysis using XRD and SEM-EDS techniques identified chemisorption as the primary adsorption mechanism, with ion exchange, surface complexation, and co-precipitation playing significant roles. These findings confirm that GBMSs, as an environmentally friendly and efficient adsorbent, holds considerable promise for the treatment of heavy metal pollution.