Applied Surface Science Advances (Dec 2023)
Recent advances and issues in the application of activated carbon for water treatment in Africa: A systematic review (2007–2022)
Abstract
Access to clean water remains a challenge in many parts of Africa. This is compounded by the increasing pollution levels with increasing population and industrialization. Activated carbon remains the most widely used adsorbent for the removal of chemical pollutants in both drinking water and wastewater treatment processes due to its unique chemical properties and a plethora of precursor materials for development. However, to date, no available literature has systematically summarized the advances in Africa on the adsorptive removal of contaminants using activated carbons and research issues such as data acquisition and presentation, analysis approaches, citations, inconsistencies and adsorption experimental setups remain largely undocumented. In this paper, adsorption studies from Africa focusing on activated carbons for the removal of various contaminants are reviewed, from 2007 to 2022. The study focused on a literature-based approach by searching key terms in selected databases. The adsorption data were mostly best described by the Langmuir and pseudo-second-order models for dyes, anions, metal ions pesticides, and pharmaceutical compounds. According to the pooled data, the highest adsorption capacity was 1552.5 mg g − 1 for PFOS adsorbed onto H3PO4-activated maize tassel-based carbon. The majority of the studies relied on linearized adsorption isotherm and kinetic models with coefficient of determination (R2) as the sole criterion for determining best-fitting models. Additionally, the majority of the studies are batch mode and laboratory-scale studies with no desorption and recyclability evaluations. Researchers should be careful to present accurate equations and units of parameters with proper citations. Pilot-scale and life cycle assessment (LCA) of the reported new materials represent an aspect largely unexplored. The fact that studies from most African countries, dating beyond 2007, could be obtained implies that activated carbons present an accessible and possibly sustainable technology for emerging economies.
