Removal of phosphate from natural waters using innovative modified bentonites

Use of modified clays for removal of phosphorus from aqueous solutions

“…The r 2 values obtained for this model were above 0.97, indicating a very good mathematical fit by the model. Similar results have been reported for the adsorption of P by modified bentonites (Zamparas et al 2012), calcium-rich sepiolite (Yin et al 2011), and pillared bentonites (Yan and Xu 2010). Values of K f for Feadsorbents were higher than those for other modified adsorbents.…”

“…Some researchers used clays for P removal from aqueous solution having high P concentration (Yan and Xu 2010;Ma and Zhu, 2006). Therefore, it is seems necessary to develop an adsorbent with high affinity for P sorption that can remove P at the lower concentrations (Zamparas et al 2012). Lin et al (2011) showed that for controlling the P release from the sediments, the mixture of calcite and CaCl 2 -pretreated zeolite as adsorbent was more efficient than that of calcite and natural zeolite alone, whereas the mixture of calcite and NaCl-pretreated zeolite was less efficient than that of calcite and natural zeolite alone.…”

“…Yan and Xu (2010) have modified bentonite with hydroxy-aluminum, hydroxy-iron, and mixed hydroxy-iron-aluminum and reported that the maximum adsorption capacity of P was 12.7, 11.2, and 10.5 mg g −1 , respectively. Zamparas et al (2012) studied removal of P from natural waters using modified bentonites and showed that P adsorption capacity of modified bentonite with Fe ions was improved by ∼350 % compared to unmodified bentonite. Haghseresht et al (2009) showed that the unmodified bentonite adsorbed negligible amount of P (<0.5 mg P g -1 ), while maximum adsorption capacity of the modified bentonite was increased at higher temperatures.…”

Removal characteristics of ammonium nitrogen from wastewater by modified Ca-bentonites

“…3. It is indicated that the adsorption of ammonium nitrogen on raw bentonite was the lowest, which should be due to higher content of impurities and lower content of exchangeable ions (Zamparas et al, 2012;Lin et al, 2013). The removal of ammonium nitrogen by the bentonite increased very fast initially with the agitation time and reached the equilibrium within 1 min.…”

A theoretical and experimental study on the P-adsorption capacity of Phoslock™

“…For the pH-edge experiments, a buffer system of 10 mM MES: (N-morpholino-ethanesulfonic acid), HEPES: (4-(2-hydroxyethyl) piperazine-1-ethanesulfonic) acid was used in all the samples [18]. This system presented a significant buffer capacity at pH range 5-8.5, with an average deviation from the adjusted pH value of 5%.…”