Environmentally friendly biosorbents (husks, pods and seeds) fromMoringa oleiferafor Pb(II) removal from contaminated water

Abstract

Lead is a heavy metal considered highly toxic, responsible for causing several health problems as well as being extremely harmful to fauna and flora. Given this fact, several techniques have been studied for the removal of this metal from contaminated water, in which stands out adsorption. In this sense, the objective of this study was to evaluate the potential of lead(II) biosorption from contaminated water by seed husks, seeds and pods of Moringa oleifera Lam (moringa). Biomass was characterized by energy-dispersive X-ray spectroscopy, Scanning Electron Microscopy and Fourier transform infrared spectroscopy analyses. From the studied parameters, the optimal conditions obtained for the three analyzed biosorbents are: 30 min to equilibrium, pH 6 and 25°C temperature. The pseudo-second-order kinetic model was the best fitted to the experimental data for the three evaluated biosorbents. Regarding the adsorption isotherms, the model that best fitted to the experimental data for seed and seed husk was that proposed by Freundlich, and for the pod the Langmuir model. The analysis of the obtained thermodynamic data showed that the adsorption process is favorable and of exothermic nature. Through the results it was concluded that the evaluated biosorbents are efficient in lead(II) biosorption.

Analysis of the influence of natural adsorbent functionalization (Moringa oleifera) for Pb(II) removal from contaminated water

“…In addition, they can assist in evaluation of modifications promoted by chemical functionalization (both acidic and basic) before the biosorption process. For this reason, the FTIR spectra obtained for the non‐functionalized MO pods (as published by Tavares et al) and after the chemical functionalization proposed in this study were presented in Figure .…”

“…In this way, the use of basic functionalized MO pods (PODB) has presented a considerable potential for removing Pb(II) from aqueous solutions. When comparing this study with Tavares et al, which also uses MO pod as biosorbent material for lead ions removal (without functionalization), chemical functionalization plays an important role in lead ions removal. Thus, a slight increase in the removal percentage for PODB and a decrease to PODA is promoted when compared to non‐functionalized biosorbent (POD).…”

“…It is possible to observe that the functionalized materials present differences in composition related to oxygen and carbon content when compared to each other. In a study developed by Tavares et al 17 using pod without chemical functionalization, it was found that oxygen content was 44.96% while carbon content was 54.44%. When comparing that result with the outcomes obtained in the present study, it was concluded that basic functionalization promoted 5% increase in oxygen content.…”

Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution

“…The other parts such as the leaves have been used as sorbent in various water treatment studies (Maina et al 2016). The seed husk has also been Responsible editor: Tito Roberto Cadaval Jr * Afrouz Bagheri bagha@uef.fi studied in the adsorption of diclofenac (Araujo et al 2018), acid black 1 and basic red 2, reactive dyes, heavy metals, atrazine, and nitrobenzene from solution (Buildings et al 1997;Akhtar et al 2007;de Carvalho et al 2015;Matouq et al 2015;Tavengwa et al 2016;Maina et al 2016;Souza et al 2016;Tavares et al 2017;Coldebella et al 2017;Khorsand et al 2017;Maria et al 2018;Shirani et al 2018).…”

Synthesis and characterization of kaolinite coated with copper oxide and its effect on the removal of aqueous Lead(II) ions

“…As a remedial measure, these wastes are stored in sealed plastic tanks under reducing condition. This process stimulates the lowering of the concentration of metals and metalloid in the slurries and leaching mud before discharge into the aquatic environment (Plescia and Maccari 1996;Tavares et al 2017). This remedial process is dependent on the oxidation-reduction state of these metallurgical wastes and has substantial effect on the leaching of elements.…”