Removal of fluoride from aqueous solution by porous Vaterite calcium carbonate nanoparticles

Abstract

This study is based on a simple, low-cost and a novel approach towards the removal of excess fluoride ions from aqueous solution by absorbing fluoride on porous vaterite calcium carbonate nanoparticles (PVCCNPs) synthesised using ethylene glycol-water soft template method. SEM images clearly show the porous nature of aggregated nanoparticles present in the dry powder. Physicochemical properties of synthesised PVCCNP and fluoride on PVCCNP was characterised further by FTIR, XRD, XRF, EDX, and TGA-DTG. Fluoride removal by PVCCNPs from 100.00 ml of 10.0 mg l −1 NaF solution with 0.500 g of PVCCNPs, determined using a fluoride ion-selective electrode, indicates that around 90% removal is achieved within 1 h thus reducing the level to desired 1 ppm. The pseudo-second order kinetic model has a better fit to describe the adsorption of fluoride on PVCCNP than pseudofirst order model. The Langmuir isotherm model is more appropriate to describe the equilibrium behaviour of the adsorption process, than the Freundlich model. Given that the value of n (Freundlich constant) is greater than 1 (3.07) and R L value is in the range of 0<R L <1 (0.014-0.024) implies that the adsorption process is spontaneous and fluoride ions are favourably adsorbed on PVCCNPs. Langmuir model shows that the maximum adsorption capacity of fluoride is 1.956 mg g −1 . Excess fluoride in drinking waters causes several severe ill-health effects and filter media based on these nanoparticles can be used to remove fluoride down to safe and required levels to tackle these health problems. As such, PVCCNPs-based filter can be designed to remove fluoride in drinking waters. This may be a way for controlling fluorosis and many other diseases associated with excess fluoride present in drinking waters.

Synthesis and Characterization of 2D Magnesium Oxide Nanoflakes: A Potential Nanomaterial for Effective Phosphate Removal from Wastewater

“…Where, q e is the amount of adsorbed ion (mg g À 1 ), q m is the maximum adsorption (mg g À 1 ), C e is the Equilibrium concentration (mg L À 1 ) and K is the Adsorption equilibrium/Langmuir constant. [85]…”

Bone char from an invasive aquatic species "devilfish" as a sustainable adsorbent for the removal of fluoride in water for human consumption

“…Fluoride pollution of water is a major issue worldwide (Akafu et al 2019;Fan et al 2019;Kumar et al 2019;Medellin-Castillo et al 2020). In drinking water, a fluoride concentration between 0.5 to 1.0 mg L -1 can be considered beneficial to teeth and bones (Abeykoon et al 2020;Medellín-Castillo et al 2020;Quintáns-Fondo et al 2019). Nevertheless, fluoride water intake above the World Health Organization (WHO) suggested dose (1.50 mg L -1 ) causes significant health effects such as dental fluorosis, skeletal fluorosis and and even in severe cases, cancer (Abeykoon et al 2020;Emmanuel et al 2018;Jalil et al 2019;Quintáns-Fondo et al 2019).…”

“…Various technologies are available for the removal of fluorides, including precipitation, coagulation, reverse osmosis, ion exchange, and adsorption. Of all methods, adsorption is highly effective and economical for the reduction of excess fluoride in water (Abeykoon et al 2020;Akafu et al 2019;Alkurdi et al 2019;Assaoui et al 2020;Emmanuel et al 2018;Fan et al 2019), and it uses a variety of adsorbent materials, including clay, soil, organic matter, alumina, zeolites, nanomaterials, activated carbon and bone char (Alkurdi et al 2019;Teusner et al 2016). Bone chars have been widely considered in fluoride removal and have gained considerable attention due to their cheapness, high availability, easy preparation and high adsorption capacity (Alkurdi et al 2019;Medellin-Castillo et al 2020).…”

Experiments on Fluometuron Removal from Simulated Agricultural Wastewater in Porous Media Filters

“…and improved the effluent quality (Stefanakis et al 2009, Bruch et al 2011Stefanakis and Tsihrintzis 2012). Furthermore, porous vaterite calcium carbonate nanoparticles (PVCCNPs) and vaterite polymorph of porous calcium carbonate nanoparticles (VPCCNPs) can be used to remove fluoride from drinking water and phosphate in natural water, respectively (Abeykoon et al 2020;Darshana-Senarathna et al 2020).…”