Síntesis de fibras de celulosa aplicados a la remoción de plomo en soluciones acuosas.

Abstract

Lead contamination in aquatic systems is an environmental problem due to its toxicity and bioaccumulation and the quest to reduce contamination through the utilization of lignocellulosic wastes has begun to gain importance. This research is based on the development of cellulose fibers obtained from banana rachis (an agricultural residue of the banana industry, and the modification of cellulose fibers with citric acid as adsorbent materials for lead. The process of obtaining the fibers was based on peeled, washed, ground, sieved, bleaching, acid hydrolysis and freeze-drying and for the modification citric acid was added in a 3:1 ratio. To characterize the fibers, physical and instrumental test were performed such as: pointe of zero charge (PZC), swelling capacity (SR%), water retention (WR%), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and pH study to determine the optimum pH for adsorption and its adsorption capacity. The characterization of FC and FC-CA revealed that pH above 2.58 and 3.53 will adsorb lead cations, the water retention capacity of FC was 80% in the first 10 minutes, by the crystallinity index it was observed that FC-CA obtained 60%, which means, that this material is more crystalline, by SEM it was observed smaller diameters in FC-CA due to its more rigid structure, in the FTIR spectra of FC revealed common functional groups in cellulose such as hydroxyl, carboxyl, methyl, C-O-C groups and β- glycosidic bonds, while FC-CA a more pronounced peak was observed at 1735.24 cm-1 confirming a modification with citric acid. The pH study revealed that optimum pH for lead adsorption for both adsorbents materials was 4, presenting an adsorption capacity of 25.73 mg/g for FC and 12.79 mg/g for FC-CA, with a removal percentage of 52% and 26%, respectively. These materials developed from the use of agro-industrial waste such as banana rachis, made it possible to obtain bioadsorbente materials for the removal of lead in aqueous solutions, being a sustainable option for wastewater to the circular economy.