Removal of Fluoride and Arsenate from Aqueous Solutions by Aluminum-Modified Guava Seeds

Abstract

Featured Application: The adsorbent materials under study could have a potential use for the decontamination of groundwater with high levels of arsenic and fluoride. It could be particularly suitable for application in water treatment for small communities.Abstract: The contamination of groundwater by arsenic and fluoride is a major problem worldwide, causing diseases in the population that uses these waters for their consumption. Therefore, the removal of these types of pollutants from groundwater is a very important issue. In this work, the removal of arsenate and fluoride from aqueous solutions by using aluminum-modified guava seeds (Al-GSs) was evaluated. Batch-type adsorption experiments were carried out with aqueous solutions of As(V) and F − and Al-GSs. The kinetic and equilibrium parameters of adsorption were determined, as well as the effects of adsorbent dose and pH. The adsorbent was characterized by scanning electron microscopy and infrared spectroscopy in order to determine its morphology and the functional groups present in the material. The results showed that hydroxyl and carboxyl are the main groups involved in the adsorption of As(V) and F − . The fluoride adsorption kinetics indicate that the equilibrium time was reached at 150 min and it can be described by the Lagergren model, while for As(V) the equilibrium time was lower (120 min) and the kinetic data were fitted well to the pseudo-second-order model. The Langmuir-Freundlich model can describe the adsorption equilibrium data in all cases. The fluoride adsorption capacity by Al-GS was 0.3445 mg/g, and for As(V) it was 4 mg/g. It can be established that the removal of arsenates and fluoride in Al-GSs is due to chemisorption on a heterogeneous surface.then consumption of these waters may lead to dental fluorosis. From 3 to 6 mg/L of fluoride, skeletal fluorosis may appear, and at higher fluoride levels (>10 mg/L) crippling skeletal fluorosis can be developed [3,4]; these types of fluorosis are irreversible, and no treatment can eliminate symptoms definitively. Keeping fluoride intake within safe levels is the only way to prevent these diseases [5,6]. People in several countries around the world are facing problems of high fluoride levels in drinking water; these problems are more severe and intense depending on different factors, like the geographical and economic status of the affected communities [7]. The World Health Organization (WHO) guidelines for drinking water quality have established that, for areas with a warm climate, fluoride concentration in water should remain below 1 mg/L, while this concentration could be raised up to 1.2 mg/ for areas with a cold climate [3]. In developing countries this problem is more acute, particularly in small urban communities and rural areas [5,8].On the other hand, arsenic content in drinking water is also a worldwide concern, and it represents a great threat to human health. Levels above 10 µg/L of arsenic, which is the maximum level recommended by the WHO, have been reported in drinking water from se...

Removal of As(V) from aqueous solutions using calcium-alginate microspheres with encapsulated iron nanoparticles

“…The Langmuir-Freundlich model is well known for describing adsorption equilibrium on heterogeneous surfaces; therefore, it can also be established that arsenate adsorption in AlgFe at different temperatures is heterogeneous. Arsenate adsorption, by similar adsorbents, has shown similar behavior as described above (Papageorgiou et al 2008;Ramos-Vargas et al 2018).…”

Removal of Arsenic using Low Cost Biosorbent Tamarind Bark

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Lignocellulosic Biomass as Sorbent for Fluoride Removal in Drinking Water

“…In the last ten years, the literature has reported pollutant ion removal from water by dry and modified lignocellulosic biomasses such as Zr-loaded orange waste gel [ 38 ], apple pomace and peel [ 19 , 22 ], wheat straw, and sawdust [ 39 ], pine sawdust [ 39 ], lemon leaves [ 40 ], several fruit peels such as banana, grape, peach, and cassava [ 24 , 41 , 42 ], tea leaves [ 43 ], jute fibers [ 44 ], guava seeds [ 45 ], sisal fiber [ 46 ], garlic husks [ 47 ], and tamarind seeds [ 48 ], among others.…”