Recent advances in synthesis and application of polymer nanocomposites for water and wastewater treatment

Synthesis of carboxymethyl cellulose-g-poly(acrylic acid)/LDH hydrogel for in vitro controlled release of vitamin B12

https://pubag.nal.usda.gov/download/61129/PDF

Farm size, seining practices, and salt use: Risk factors for Aeromonas hydrophila outbreaks in farm-raised catfish, Alabama, USA

Effective modelling of the fate and transport of water-borne pathogens is needed to support federally required pollution-reduction plans, for water quality improvement planning, and to protect public health. Lack of understanding of microbial-particle interactions in water bodies has sometimes led to the assumption that bacteria move in surface waters not associated with suspended mineral and organic particles, despite a growing body of evidence suggesting otherwise. Limited information exists regarding the factors driving interactions between micro-organisms and particles in surface waters. This review discusses cellular, particle and environmental factors potentially influencing interactions and in-stream transport. Bacterial attachment in the aquatic environment can be influenced by properties of the cell such as genetic predisposition and physiological state, surface structures such as flagella and fimbriae, the hydrophobicity and electrostatic charge of the cell surface, and the presence of outer-membrane proteins and extracellular polymeric substances. The mechanisms and degree of attachment are also affected by characteristics of mineral and organic particles including the size, surface area, charge and hydrophobicity. Environmental conditions such as the solution chemistry and temperature are also known to play an important role. Just as the size and surface of chemical particles can be highly variable, bacterial attachment mechanisms are also diverse.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1935&context=abe_eng_pubs

Cellular, particle and environmental parameters influencing attachment in surface waters: a review.

Enhancing atrazine biodegradation by Pseudomonas sp. strain ADP adsorption to Layered Double Hydroxide bionanocomposites.

Mg-Al layered double hydroxide was entrapped in calcium alginate beads (LDH-alginate beads) for phosphate removal. A field emission scanning electron microscope (FESEM), combined with an energy dispersive X-ray spectrometer and an X-ray diffractometer, were used to analyze the properties of LDH-alginate beads. Batch and flow-through column experiments were performed to examine phosphate removal in LDH-alginate beads. FESEM images show that the cross-sectional surface of LDH-alginate beads was heterogeneous in surface topography, and LDH powders were intermingled with alginate polymers. Experimental results indicate that Mg-Al LDH-alginate beads are effective in the removal of phosphate. Batch experiments indicate that phosphate removal in 8% LDH-alginate beads was not sensitive to initial solution pHs between 4.9 and 8.9. Kinetic experiments demonstrate that phosphate removal reached equilibrium around 12 h of reaction time. Column experiments show that the removal capacity of 8% LDH-alginate beads was tw...

/pdf/entrapment-of-mg-al-layered-double-hydroxide-in-calcium-389j31lofv.pdf

Entrapment of Mg-Al layered double hydroxide in calcium alginate beads for phosphate removal from aqueous solution

Column experiments were performed to investigate the effect of ionic strength on the attachment and detachment of Staphylococcus aureus ATCC 10537 and Bacillus subtilis ATCC 6633 in aluminum-coated quartz sand. Results showed that the average mass recovery decreased from 80.7 to 45.3% in quartz sand and remained constant in aluminum-coated sand with increasing ionic concentrations of sodium chloride solution from 1 to 100 mmol/L. As the ionic concentrations of leaching solution changed from 100 to 0.1 mmol/L, average mass recovery of 39.1% was obtained from quartz sand (bacterial release), but no detachment was observed from aluminum-coated sand. This lack of detachment can be attributed to inner-sphere complexes between bacteria and aluminum-coated sand, which are minimally affected by ionic strength. This research indicates that aluminum-coated sand has advantages over quartz sand in bacteria removal in water filtration systems.

Bacterial attachment and detachment in aluminum-coated quartz sand in response to ionic strength change.

Column experiments were performed in this study to investigate the influence of ionic strength on the mass recovery of Escherichia coli in iron-coated sand. The first set of the experiments was per...

Determination of bacterial mass recovery in iron-coated sand: influence of ionic strength.

The aim of this study was to investigate the influence of ionic strength and iron impregnation on the attachment of Enterococcus faecalis to granular activated carbon (GAC). Column experiments were performed to examine bacterial adhesion to coconutbased GAC (c-GAC), iron-impregnated c-GAC (fc-GAC), acid-washed c-GAC (a-GAC) and iron-impregnated a-GAC (fa-GAC) under two different solution (NaCl 1, 10 mM) conditions. Results showed that bacterial mass recovery in c-GAC decreased from 77.3 to 61.6% while in a-GAC it decreased from 71.6 to 32.3% with increasing ionic strength from 1 to 10 mM. This indicates that bacterial attachment to GAC can be enhanced with increasing ionic strength. Results also showed that the mass recoveries in fc-GAC were 62.6% (1 mM) and 53.3% (10 mM) while they were 50.8% (1 mM) and 16.9%(10 mM) in fa-GAC, which were lower than those in c-GAC and a-GAC. This demonstrates that bacterial adhesion to GAC can be enhanced through iron impregnation. This study provides information regarding the effects of ionic strength and iron impregnation on bacterial attachment to GAC. Furthermore, this study will advance our knowledge of bacterial removal in surface-modified granular media.

Analysis of Enterococcus faecalis Attachment to Granular Activated Carbon with a Column Experiment

This study investigated the influence of ionic strength on the adhesion and release of bacteria (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus) in quartz and iron-coated sands using column experiments. Results show that the mass recovery remained constant (E. coli = 13.7±0.5%, B. subtilis = 9.8±1.3%, S. aureus = 13.0±2.1%) in iron-coated sand while it decreased from 80.7 to 45.3% (S. aureus) in quartz sand with increasing ionic concentrations from 1 to 100 mM. As the ionic concentrations of leaching solution was lowered from 100 to 0.1 mM, average 39.1% of bacterial detachment was quantified from quartz sand, but no bacterial release was observed in iron-coated sand. The phenomenon observed in iron-coated sand can be attributed to the inner-sphere complexes between bacteria and coated sand, which have minimal effect from ionic strength. This study improves our knowledge regarding the bacterial interaction with surface-modified porous media.

http://www.jksee.or.kr/upload/pdf/KSEE_1_2009_04_287(C).pdf

Yong-Un Han

Papers

Entrapment of Mg-Al layered double hydroxide in calcium alginate beads for phosphate removal from aqueous solution

Bacterial attachment and detachment in aluminum-coated quartz sand in response to ionic strength change.

Determination of bacterial mass recovery in iron-coated sand: influence of ionic strength.

Analysis of Enterococcus faecalis Attachment to Granular Activated Carbon with a Column Experiment

Adhesion and Release of Bacteria in Quartz and Iron-coated Sands: Effect of Ionic Strength