Cellulose emerges as an alternative for the treatment of water contaminated with heavy metals due to its abundant biomass and its proven potential in the adsorption of pollutants. The aquatic plantEichhornia crassipesis an option as raw material in the contribution of cellulose due to its enormous presence in contaminated wetlands, rivers, and lakes. The efficiency in the removal of heavy metals is due to the cation exchange between the hydroxyl groups and carboxyl groups present in the biomass ofE. crassipeswith heavy metals. Through different chemical and physical transformations of the biomass ofE. crassipesThe objective of this review article is to provide a discussion on the different mechanisms of adsorption of the biomass ofE. crassipesto retain heavy metals and dyes. In addition to estimating equilibrium, times through kinetic models of adsorption and maximum capacities of this biomass through equilibrium models with isotherms, in order to design one biofilter for treatment systems on a larger scale represented the effluents of a real industry.

The aim of this work is to design a fixed-bed column with vegetal biomass of Eichhornia crassipes and the process of recycling it for treatment via the adsorption of water loaded with chromium (VI). In the first stage, the relationship between the fixed-bed density and the microparticle density is calculated, giving a model for the design of the fixed bed. Using this model, two systems for the treatment of Cr (VI)-contaminated water were designed and built. The vegetable biomass at three particle diameters of 0.212 mm, 0.30 mm and 0.45 mm was evaluated in the removal of Cr (VI) from water using the designed fixed-bed systems, giving the best removal of Cr (VI) with the lowest size particles and allowing the validation of the proposed model with the Thomas model. The incorporation of iron into the biomass allowed for the treatment of near 2.0 L of polluted solution, removing around 90% of Cr (VI), while it was only possible to treat nearly 1.5 L when using raw biomass, removing around 80% of Cr (VI). The recycling of the biomass was achieved via the elution of Cr (VI) with EDTA, permitting the reuse of the material for more than five treatment cycles.

: The purple Cameroon grass crop (P. purpureum cv. Morado) presents significant potential as a source of raw materials and renewable energy; it has rapid growth, high yield, and low fertilizer demand. During the conversion of lignocellulosic biomass, hemicellulose and cellulose can first be hydrolyzed into five and six-carbon sugars, and then the sugars are converted into furfural and levulinic acid (LA) respectively. In this work, the furfural and levunilic acid production was evaluated in a two-stage catalytic process with a tin catalyst supported on a sulfonated activated carbon. In the first stage, a furfural yield of 23.28% at 170 °C for 3 h. In the second stage, the effect of process temperature and time on LA production's yield and energy demand was evaluated; LA yield of 28.17% was obtained with an energy demand of 0.12 kWh/gLA at 180.47 °C for 1.78 h. These results demonstrate the possibility of obtaining furfural from Cameroon grass. Graphical Abstract