An empirical literature analysis of adsorbent performance for methylene blue uptake from aqueous media

Methylene blue (MB) is a heterocyclic aromatic compound used as a medication or as a synthetic dye for textiles. Due to its ecotoxicity, researchers have been investigating its mitigation by the adsorption process. The aim of this review was to analyse the performance of different classes of adsorbent for MB dye uptake based on their maximum adsorption capacity. MB was chosen for this analysis due to the large volume of work that has been done on it over the years. Over 500 research papers published on MB adsorption (within the past 5 years were analysed). This was to help guide the research area on the best class adsorbents for MB uptake thereby pointing the areas of biggest potential to investigators. Composites adsorbents (31%) were the most frequently studied for MB uptake. Other popularly used types were biosorbents (16%) and activated carbon (16%). Polymers and resins, and organic and inorganic nanoparticles were the more favoured constituents for composite adsorbent development. For similar data indices, composite adsorbents yielded a higher adsorption capacity. This suggests that composite adsorbents (especially with constituents of polymers, resins and nanoparticles) perform better for MB uptake. Though polymers and resins had the highest mean, the highest median was for activated carbon. Composite adsorbent was the second highest for mean, median and number of adsorbents above the 1000 mg/g threshold. It was surmised from the analysis that polymers, resins and composites are the best classes of adsorbents for MB uptake.

Automated summary

This review focused on the performance of different classes of adsorbent for MB dye uptake, with composite adsorbents showing the highest adsorption capacity, especially those containing polymers, resins, and nanoparticles. The analysis indicates that polymers, resins, and composites are the best classes of adsorbents for MB uptake.