Interaction of surfactant-modified zeolites and phosphate accumulating bacteria

Biosorption of phosphate from synthetic wastewater by biosolids

“…The highest number of immobilized cells was obtained with 2OB (7.78 x 10 9 CFU/g). This is somewhat higher than the reported 6.86 x 10 9 CFU/g of A. calcoaceticus immobilized onto the magnesium-exchanged natural zeolite [10], 5.28 x 10 9 CFU/g of A. junii immobilized onto CTA modified natural zeolite [14], 2.9 x 10 9 CFU/g of Acinetobacter spp. immobilized onto ceramics by the vacuum method [9], 2.5 x 10 8 CFU/g of A. johnsonii cells immobilized inside alginate beads [8] or 9 x 10 8 CFU/g of P. aeruginosa immobilized onto a type-Z carrier consisting of silica alumina matrix containing zeolite [13].…”

“…Each carrier was aseptically placed in a tube containing 9 ml of sterile 0.3% NaCl, crushed with a sterile glass rod and dispersed by shaking (2700 rpm/10 min). This procedure, similar to [13,14], removed the immobilized cells so that they remained as individual cells on the carrier (compared to the previous multilayer cell coverage of material, more than 10 μm thick), which was confirmed by microscopy. Suspensions of immobilized cells prepared in this way were serially diluted (10 -1 to 10 -9 ).…”

Phosphate uptake from water on a Surfactant-Modified Zeolite and Ca-zeolites

“…Among the latter, two main methods can be distinguished, either chemical precipitation [7,8] by aluminum or iron salts or by lime, or adsorption and/or ion exchange reactions on a variety of materials. These materials are either natural, for instance dolomite [9], soils [10], residues of blast furnaces [11], coal fly ashes [12]… or synthetic, namely activated carbons [13], iron or aluminum hydroxides [14,15], biopolymers [16]… Apart from these materials, compounds characterized by an organized porosity, either zeolitic (natural [17][18][19] or synthetic [20][21][22][23][24]) or mesostructured (functionalized) [25,26] were also used. With the notable exception of the mesostructured functionalized materials, the preparation of which is rather difficult and expensive, all the phosphate adsorption processes, implying in particular zeolitic materials, are clearly promising as they operate under economical and simple conditions.…”

“…The sorbed surfactant species form bilayers on the zeolite crystals surface, with the first layer retained by cation exchange, the second layer being attached by hydrophobic bonding (van der Waals forces) and stabilized by counteranions. SMZ can thus be used as anionic exchangers to adsorb a variety of anions, such as chromate, antimonate, arsenate, selenate, phosphate and nitrate… [18,19,[27][28][29][30][31][32][33][34]. Taking into account this ion-exchange sorption mechanism, the regeneration of SMZ can be easily performed, which is also very important in the perspective of industrial applications.…”

“…To our knowledge, the number of papers specifically devoted to the sorption of phosphate ions on SMZ is rather low, and imply the use of clinoptilolite zeolite [18,19] or of LTA-type zeolite [33]. SMZ prepared from clinoptilolite is only employed in batch-wise experiments, Hrenovic et al [19] dealing more precisely with the interaction of SMZ and phosphate-accumulating bacteria in the phosphorus removal from wastewaters.…”