Phosphate Adsorption by Montmorillonites Modified with Lanthanum/Iron and a Laboratory Test using Water from the Jacarepaguá Lagoon (RJ, Brazil)

Abstract

Montmorillonites modified with lanthanum(III) and iron(III) were prepared from two commercial clays. These materials were characterized by powder X-ray diffraction analysis, X-ray fluorescence, infrared spectroscopy, N 2 adsorption, and scanning electron microscopy. The incorporation of lanthanum(III) and iron(III) varied from 0 to 4.00%. The amount of these cations governed the adsorption capacity of the material since an increase in the percentage of La by 1.7 times improved the adsorption capacity by 3.3 times. The structural properties of the precursor clay minerals, such as pore size, may have influenced the extension of the modification process. Kinetics and equilibrium studies indicated that adsorption occurs mainly within 24 h, and the pseudo-second order and Lagmuir models described the process. The phosphate adsorption capacity ranged from 2.86 to 17.86 mg g-1 for the modified materials and was mainly dependent on the La content. A laboratory test with a natural water sample from the Jacarepaguá Lagoon showed reduction of the soluble reactive phosphorus concentration from 0.41 to 0.04 mg L-1 , for the material with 4.00% La 2 O 3. The materials described in this work were effective for the reduction of the soluble reactive phosphate, contributing to the research of a national product destined to the restoration of eutrophic aquatic environments.

Plasticized magnetic starch-based Fe3O4 clay polymer nanocomposites for phosphate adsorption from aqueous solution

“…The black clay soils CEC were (~20 meq/100g soil) higher than red clay soils. The observed clay soils CEC values were within the previously reported range (De Castro et al, 2019). NC was prepared through the ion exchange method described in Manocha et al (2008) and Shirsath et al (2011).…”

“…Among the pollutants, P is the major nutrient for sustaining life on earth (Waweru et al, 2019) and the normal functioning of the ecosystem (Liu and Zhang, 2015). However, excess phosphate concentration of P as 0.02-0.39 mg P/L causes eutrophication, pollutes the water bodies, and 0.75-1.20 mg P/L is called hypereutrophic (De Castro et al, 2019;Yang et al, 2019). As a result, in most countries, recommended effluent phosphate concentrations were generally <2 mg P/L despite variation based on the receiving water bodies sensitivity: for example, European Union, directive 91/271/EE endorses 1-2 mg P/L of total phosphorus (TP) in the discharge effluent (Peleka and Deliyanni, 2009).…”

“…As a result, in most countries, recommended effluent phosphate concentrations were generally <2 mg P/L despite variation based on the receiving water bodies sensitivity: for example, European Union, directive 91/271/EE endorses 1-2 mg P/L of total phosphorus (TP) in the discharge effluent (Peleka and Deliyanni, 2009). In cells, phosphorus is found as ATP (adenosine triphosphate) and DNA/RNA (deoxyribonucleic acid/ribonucleic acid), whereas in water available as particulate and dissolved phosphate: organic or inorganic (orthophosphate or soluble reactive) (De Castro et al, 2019). So far, several technologies have been developed to remove P. Relative to available technologies, adsorption is considered an effective P removal method due to its simplicity in operation and economical (Peleka and Deliyanni, 2009), fast and high removal efficiency at trace level (Huang et al, 2017), and produce less amount of sludge (Jiang et al, 2013).…”

Fe(III)-polyhydroxy cations supported onto K10 montmorillonite for removal of phosphate from waters

“…Tian et al (2009) investigated the use of bentonite pillared with Al 3þ and mixtures of Al 3þ and La 3þ polyhydroxy cations, finding that the mixed systems provided higher adsorption capacities. de Castro et al (2018) investigated the intercalation of two montmorillonites with mixtures of La 3þ and Fe 3þ , stating that the use of Fe 3þ is economically advantageous since Fe 3þ salts are less expensive than La 3þ ones. However, modification with La 3þ renders materials that are not susceptible to redox reactions.…”

Technological Evaluation of Cubati/Brazil Montmorillonite / Avaliação Tecnológica Da Montmorillonita De Cubati/Brasil

“…The authors [54], for example, investigated and compared the effect of montmorillonite content in a natural Arabian clay with a bentonite, and the results showed that the natural clay presented 20.83 m 2 g -1 of surface area against 44.28 m 2 g -1 of bentonite surface area. Others authors [55] studied the modification of commercial montmorillonites with lanthanum (III) and iron (III), obtaining values of average pore size and pore volume in the range of 59.0 to 74 Å and 0.09 to 0.16 cm 3 g -1 , respectively.…”