Seaweed as a Sustainable Biosorbent for Heavy Metal Removal in Wastewater Treatment: A Bibliometric and Thematic Analysis

Seaweed has garnered significant attention as a sustainable and efficient biosorbent for removing heavy metals from wastewater, offering a low-cost and eco-friendly alternative to conventional treatment methods. However, despite increasing research interest, substantial gaps remain in understanding the large-scale applicability, adsorption mechanisms in multi-contaminant systems, and long-term sustainability. Furthermore, studies on biosorbent modification techniques, process optimization, and techno-economic feasibility assessments are limited, hindering the transition from laboratory research to industrial-scale applications. To address these gaps, this study conducts a bibliometric analysis using R’s Biblioshiny package and VOSviewer for data processing and visualisation, focusing on the integration of seaweed for heavy metal removal. The analysis is based on 369 documents retrieved from the Web of Science (WoS) database from 2014 to 2024. It identifies four major research clusters, highlighting key thematic trends and knowledge gaps. While biosorption remains a core research area, studies on biosorbent enhancement, large-scale implementation, and real-world wastewater treatment are underdeveloped. Thematic mapping reveals limited disruptive innovations, particularly in reactor design optimization, continuous processing systems, and biosorbent regeneration technologies. These limitations constrain scalability and integration into existing industrial wastewater treatment infrastructures. The international co-authorship rate of 34.15% underscores global interest, yet low single-author output (eight documents) indicates reliance on collaborative research. The mean citation rate of 39.85 per document indicates the increasing academic significance of biosorption; nonetheless, the absence of dominant themes implies a gradual shift towards industrial implementation. This study systematically evaluates research gaps and outlines future directions to enhance scalability and industrial viability of biosorption. The insights serve as a roadmap for researchers and policymakers, guiding efforts toward innovative and sustainable wastewater treatment solutions. Uniquely, this work integrates bibliometric analysis and thematic evaluation to propose strategic future directions essential for advancing seaweed-based biosorption towards practical industrial applications.