Abstract: Background and Objective: Incessant increase in the pollution of water bodies due to brilliant green dye (BGD) discharge from forms of industrial activities has called for its adsorption isotherm parameter prediction for efficient design of equipment for BGD uptake from aqueous solution. In this study, a low-cost composite adsorbent was prepared from snail shell and rice husk (SS-RH) via calcination for brilliant green dye (BGD) adsorption from aqueous solution. Materials and Methods: Six two-parameter and three three-parameter isotherm models were used to fit the experimental data by both linear and non-linear regression methods using 10 error functions. The SEM, FTIR and EDS were used to characterize the adsorbent. Results: Langmuir and Sip were the most fitted isotherm models for the process. Chi-square (χ2) predicted well for two-parameter isotherm study while EABS, HYBRID and NSD predicted well for non-linear R-P, Sips and Toth models, respectively. The SEM revealed irregular surface texture for the SS-RH with pore openings filled with BGD. The FTIR revealed shift in spectrum broad peaks after adsorption. Active mixed metal oxides were formed with change in weight percentage after adsorption by EDS. Conclusion: Predicted isotherm parameters proved applicable for effective adsorption column design. Statistical error functions were efficient to tackle discrepancies of data arising from measurement error. Also, snail shell-rice husk adsorption capacity and surface properties proved it as effective adsorbent for brilliant green dye removal from aqueous solution.