Heavy metal-containing industrial effluents, such as Pb2+, Cd2+, and Cu2+, pose serious threats to the environment and public health since they are not biodegradable and can accumulate over time. Biochar, particularly sewage sludge-derived biochar (SSBC), has arisen as a promising and cost-effective material for heavy metal removal from wastewater due to its high adsorption capacity, large surface area, and rich porous structure. This review explores the use of SSBC for the adsorption of heavy metals, highlighting the impact of pyrolysis temperature on its surface properties, such as specific surface area and functional groups. Characterization techniques, including SEM, FTIR, XRD, XPS, AES, GC–MS, ICP, and ESR, are employed to analyze the chemical and structural properties of SSBC, providing insights into the changes that enhance its adsorption performance. Additionally, Artificial Neural Network (ANN) models are utilized to portend the adsorption efficiency of SSBC, offering a quantitative understanding of the relationship between heavy metal removal efficiency and biochar properties. This review emphasizes the importance of pyrolysis in optimizing SSBC for wastewater treatment and demonstrates how advanced characterization techniques and predictive models can guide the progress of more efficient biochar-based adsorbents for environmental remediation. The results highlight the promising role of SSBC in providing a sustainable remedy for heavy metal contamination in industrial wastewater.