Use of a La(III)-modified bentonite for effective phosphate removal from aqueous media.
A bentonite from the Northeast Brazilian region was modified with lanthanum (NT-25La) using an ion exchange process. Lanthanum incorporation in the natural clay, as well as the properties of the clay materials, were confirmed by X-ray diffraction, X-ray fluorescence, specific surface area and scanning electron microscopy (SEM/EDX). Phosphate adsorption equilibrium and kinetic tests were performed at different temperatures. The adsorption data have shown that NT-25La reaches equilibrium between modified clay and phosphate solution within 60 min of contact. The phosphate retention at room temperature reached 95%, when initial phosphate concentration in solution was 5 mg L(-1). A kinetic-order variable model provided satisfactory fitting of the kinetic data. Adsorption of phosphate was best described by a Langmuir isotherm, with maximum phosphate sorption capacity of 14.0 mg g(-1). Two distinct adsorption mechanisms were observed that may influence the adsorption processes. The investigation pointed out that the phosphate adsorption occurs via physisorption processes and that the use of NT-25La provides a maximum phosphate sorption capacity higher than many commercial adsorbents.
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, Santo André CEP 09210-170, SP, Brazil.
Vivian
V
Kuroki
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, Santo André CEP 09210-170, SP, Brazil.
Giulianna E
GE
Bosco
Laboratório de Biogeoquímica Ambiental, Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Cx. Postal 676, São Carlos CEP 13565-905, SP, Brazil.
Pedro S
PS
Fadini
Laboratório de Biogeoquímica Ambiental, Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Cx. Postal 676, São Carlos CEP 13565-905, SP, Brazil.
Antonio A
AA
Mozeto
Department of Chemistry/CCET, Universidade Federal de Sergipe, São Cristóvão CEP 49100-000, SE, Brazil.
Antonio R
AR
Cestari
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, Santo André CEP 09210-170, SP, Brazil. Electronic address: wagner.carvalho@ufabc.edu.br.
Wagner A
WA
Carvalho
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007811:Lanthanum / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D010710:Phosphates; D014874:Water Pollutants, Chemical; D001546:Bentonite; D007811:Lanthanum
Adsorption; Lanthanum; Modified bentonites; Phosphate; Remediation