In this work, SiO2 nanoparticles were prepared by the sol-gel method after sodium silicate was extracted from rice husk ash (RHA) under various experimental conditions such as types of acids, NaOH concentration, dissolved time, and temperature and used for removal of Fe2+ ions from aqueous solutions. The extracted SiO2 was morphologically and chemically characterized and showed a surface area of 78 m2/g and uniform pores of 2.71 nm, offering high adsorption capacity for Fe2+ ions. The influence of pH, contact time, and amount of adsorbent was studied in order to establish the best conditions for the Fe2+ adsorption and removal. Furthermore, the adsorption data were fitted with an exponential shape curve for all the three variable parameters that affect the adsorption process. The best results were obtained for pH 5, 20 min contact time, and 0.5 g adsorbent dose. The loading adsorption capacity was 9 mg of Fe2+ ions/g SiO2 in the concentration range 0.1-1.0 mgL-1. In addition, the synthesized SiO2 with the size of around 50 nm can be used for specific heavy metal removal and drug delivery, after modification of the SiO2 surface with various functional groups.
With the growing prevalence of type 2 diabetes, particularly in emerging countries, its management in the context of available resources should be considered. International guidelines, while comprehensive and scientifically valid, may not be appropriate for regions such as Asia, Latin America or Africa, where epidemiology, patient phenotypes, cultural conditions and socioeconomic status are different from America and Europe. Although glycaemic control and reduction of micro- and macrovascular outcomes remain essential aspects of treatment, access and cost are major limiting factors; therefore, a pragmatic approach is required in restricted-resource settings. Newer agents, such as sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists in particular, are relatively expensive, with limited availability despite potentially being valuable for patients with insulin resistance and cardiovascular complications. This review makes a case for the role of more accessible second-line treatments with long-established efficacy and affordability, such as sulfonylureas, in the management of type 2 diabetes, particularly in developing or restricted-resource countries.