Removal of arsenate from water by adsorbents: a comparative case study

Abstract

Laboratory and field filtration experiments were conducted to study the effectiveness of As(V) removal for five types of adsorbent media. The media included activated alumina (AA), modified activated alumina (MAA), granular ferric hydroxide (GFH), granular ferric oxide (GFO), and granular titanium dioxide (TiO₂). In laboratory batch and column experiments, the synthetic challenge water was used to evaluate the effectiveness for five adsorbents. The results of the batch experiments showed that the As(V) adsorption decreased as follows at pH 6.5: TiO₂ > GFO > GFH > MAA > AA. At pH 8.5, however, As(V) removal decreased in the following order: GFO = TiO₂ > GFH > MAA > AA. In column experiments, at pH 6.5, the adsorbed As(V) for adsorbents followed the order: TiO₂ > GFO > GFH, whereas at pH 8.5 the order became: GFO = TiO₂ > GFH when the challenge water containing 50 μg/L of As(V) was used. Field filtration experiments were carried out in parallel at a wellhead in New Jersey. Before the effluent arsenic concentration increased to 10 μg/L, approximately 58,000 and 41,500 bed volumes of groundwater containing an average of 47 μg/L of As(V) were treated by the filter system packed with GFO and TiO₂, respectively. The As(V) adsorption decreased in the following sequence: GFO > TiO₂ > GFH > MAA > AA. Filtration results demonstrated that GFO and TiO₂ adsorbents could be used as media in small community filtration systems for As(V) removal.

Engineering metal (hydr)oxide sorbents for removal of arsenate and similar weak-acid oxyanion contaminants: A critical review with emphasis on factors governing sorption processes

“…Sorbents represent an ideal platform for engineering simple and inexpensive systems capable of simultaneously removing multiple harmful weak-acid oxyanions from complex water matrices. In the last two decades, there has been a rapid expansion in development of novel sorbents for treatment of weak-acid oxyanions (Bang et al, 2011;Ippolito et al, 2011;Mohan and Pittman, 2007;Möller, 2011;Westerhoff et al, 2006). However, the majority of this work has been based on the trial and error approach, rather than on a fundamental understanding of the physico-chemical principles that govern the performances of a sorbent in a given groundwater matrix (Bleiman and Mishael, 2010;Camacho et al, 2011;Diamadopoulos et al, 1993;Duc et al, 2006;Gibbons and Gagnon, 2011;Kamei-Ishikawa et al, 2008;Maeda et al, 1990;Monteil-Rivera et al, 2000;Ramana and Sengupta, 1992;Park and Kim, 2011;Pillewan et al, 2011;Pirilä et al, 2011;Prathap and Namasivayam, 2010;Saikia et al, 2011;Sari et al 2012;Suzuki et al, 1997;Li et al 2011;Ma and Tu, 2011;Mariussen et al, 2012;Mohan and Pittman, 2007;Mostafa et al, 2011;Mou et al, 2011;Rovira et al, 2008;Tanboonchuy et al, 2011;Watkins et al, 2006;Wei et al, 2012;Yang et al 2011;Zhang et al, 2009aZhang et al, , 2009bZheng et al, 2011).…”

Evaluating adsorption media for simultaneous removal of arsenate and cadmium from metallurgical wastewater

“…Among these techniques, adsorption is considered a suitable water treatment technology and has been widely employed because of its feasible operation and the availability of a wide range of adsorbents [11][12][13][14]. However, a major concern for application of the adsorption method is how to select the most suitable adsorbent among various candidates because different media have distinct adsorption capacities and reaction mechanisms [13][14][15][16][17][18]. The great divergence in their adsorption capacity and suitability in previous reports highlights the importance of a side-by-side comparison of their adsorption effectiveness in wastewater treatment.…”

“…The effectiveness of different adsorbent media for groundwater As removal has been evaluated and follows the order TiO2 > GFO > AA at pH 6.5; whereas the order changes to GFO = TiO2 > AA at pH 8.5 [15]. nZVI has been demonstrated as an effective scavenger for heavy metals in groundwater and wastewater [24][25][26].…”

Synthesis and Evaluation of a Novel Hybrid Polymer Containing Manganese and Iron Oxides as a Sorbent for As(III) and As(V) Removal

“…In order to confirm our suppositions concerning the diffusion factors as the rate-limiting step, the experimental data were additionally analyzed using the intraparticle diffusion model. It can be expressed as follows: 36,40 = + q k t c t id 0.5 (10) where k id is the intraparticle diffusion rate constant, q t is the fraction of arsenic uptake, and c is the intercept. If the plot of q t versus t 0.5 is a straight line and the intercept c passes through the origin, the sole rate-limiting step during the adsorption process is the pore diffusion.…”