Preconcentration of Trace Arsenite and Arsenate with Titanium Dioxide Nanoparticles and Subsequent Determination by Silver Diethyldithiocarbamate Spectrophotometric Method

Abstract

A novel method of preconcentration of trace arsenite and arsenate by using titanium dioxide nanoparticles as adsorbent was described. The concentrations of preconcentrated arsenite and arsenate were determined by a silver diethyldithiocarbamate spectrophotometric method without desorption. Batch adsorption experiments were carried out as a function of the pH, contact time, amount of titanium dioxide nanoparticles, and solution volume. In the pH range 5 to 6, adsorption rates of arsenite and arsenate were higher than 98%. The calibration coefficient was 0.9991, and the linear range was 0 to 100 μg/L. The developed method was precise, with the relative standard deviation <5% at concentration level of 10 μg/L, with a detection limit (3σ, n = 6) of 0.44 μg/L. The accuracy of the method for total arsenic was validated by standard reference materials (SRM 3103a) (National Institute of Standards and Technology, Gaithersburg, Maryland). The method was also applied to the analysis of arsenite and arsenate in natural water samples to verify the accuracy. The recovery values remained in a narrow range, from 95 to 103%.

Synthesis, characterization and adsorption behavior of Mo(VI) and W(VI) ions on titanium dioxide nanoparticles containing anatase modification

“…Surfaces of metal oxides usually have positive charge at low pH (our case: pH 0.35, i = 0.43(1), i-ionic strength). Mo(VI) and W(VI) ions in hydrated associates of different compositions probably have a negative charge (a similar to As(V) and Mo(VI) ions (Valencia-Trejo et al 2010;Deedar et al 2009;Xiao et al 2007;Von Tytko et al 1983). At low temperatures, they are adsorbed at the expense of forces of electrostatic character.…”

“…One of the most efficient, applicable and low cost methods for the removal of toxic metals from aqueous solutions is their adsorption on an inorganic adsorbent. Nanosized titanium dioxide attracts interest due to high speed of As(III) and As(V) (Dadachov 2006a, b;Meng et al 2003), As(V) (Valencia-Trejo et al 2010;Deedar et al 2009;Xiao et al 2007), U(VI) (Dadachov 2006a, b), Bi(V) , (Cu(II) (Georgaka and Spanos 2010), V(V) (Tella et al 2010), Cu(II) and Mn(II) (Bleam and McBride 1986), Cd(II) (Gao et al 2004) extracting from aqueous solutions. To achieve high efficiency of adsorption, it is important to understand the effect of the solution parameters and characteristics of adsorbents.…”

Alloyed AuFeZnSe quantum dots@gold nanorod nanocomposite as an ultrasensitive and selective plasmon-amplified fluorescence OFF-ON aptasensor for arsenic (III)

“…In the past three decades, there have been several instrumental techniques and chemical methods that have been developed for As. Molybdenum blue [17], silver diethyldithiocarbamate, and the [18] Gutzeit test, [19] are the three most commonly used colorimetric chemical methods for arsenic recognition. These methods, though common, are not overly selective to arsenic and their limit of detection (LOD) does not meet the WHO's recommended limit for arsenic recognition [20].…”