This study exhibits several methodological and statistical inconsistencies that undermine its validity and reliability. The ANOVA table reveals that interaction and quadratic terms in the response surface model lack statistical significance (p > 0.05), suggesting their inclusion might artificially inflate the model’s R² value (0.9019) without substantive contribution. Additionally, the study omits critical details about randomization, replication, and blocking in its Box-Behnken design, which are essential to control experimental bias. This, combined with substantial variability in reported HHA yields under identical conditions, raises concerns about the reproducibility of the results. Furthermore, the quantification of humic acid yields lacks error propagation analysis, and the narrow experimental ranges for parameters such as temperature and KOH ratios are inadequately justified against broader ranges cited in key references. These issues question the robustness of the experimental approach and the reliability of the conclusions.
