Evaluating the Ecological Footprint of Landfills: A Framework and Case Study of Fargo, North Dakota.

There is growing interest in better understanding the environmental impacts of landfills and optimizing their operation. Accordingly, we developed a holistic framework to calculate a landfill's Ecological Footprint (EF) and applied that to the Fargo, North Dakota, landfill. Parallelly, the carbon footprint and biocapacity of the landfill were calculated. We calculated the EF for six scenarios (i.e., cropland, grazing land, marine land, inland fishing ground, forest land, and built land as land types) and six operational strategies typical for landfills. Operational strategies were selected based on the variations of landfill equipment, the gas collection system, efficiency, the occurrence of fugitive emissions, and flaring. The annual EF values range from 124 to 213,717 global hectares depending on land type and operational strategy. Carbon footprints constituted 28.01-99.98% of total EF, mainly driven by fugitive emissions and landfill equipment. For example, each percent increase in Fargo landfill's fugitive emissions caused the carbon footprint to rise by 2130 global hectares (4460 tons CO2e). While the landfill has biocapacity as grazing grass in open spaces, it remains unused/inaccessible. By leveraging the EF framework for landfills, operators can identify the primary elements contributing to a landfill's environmental impact, thereby minimizing it.

Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials.

The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed higher dynamic load induced piezo-responses with significantly improved consistency and less hysteresis in the cementitious materials. When compared with the samples prepared with the surfactant method, the samples made by the developed CCNTs showed slightly increased force detection sensitivity with significantly improved consistency in piezo-response and only minor hysteresis, indicating enhanced dispersion effectiveness. The new CNT surface coating method can be scaled up easily to cater the potential industry needs for future wide application of smart cementitious materials.

Modeling arsenic removal by nanoscale zero-valent iron.

Arsenic removal by nanoscale zero-valent iron (NZVI) was modeled using the USGS geochemical program PHREEQC. The Dzombak and Morel adsorption model was used. The adsorption of As(V) onto NZVI was assumed to happen because of the hydrous ferric oxide (Hfo) which was the surface oxide for the model. The model predicted results were compared with the experimental data. While the experimental study reported that 99.57% arsenic removal by NZVI, the model predicted 99.82% removal which is about 0.25% variation. All the arsenic species have also been predicted to be significantly removed by adsorption onto NZVI surface. The effect of pH on As(V) removal efficiency was also evaluated using the model and it was found that above point-of-zero-charge (PZC), the adsorption of As(V) decreases with the increase of pH. The authors conclude that PHREEQC can be used to model contaminant adsorption by nanomaterials.

Removal of aqueous cyanide with strongly basic ion-exchange resin.

The removal of cyanide (CN-) from aqueous solutions using a strongly basic ion-exchange resin, Purolite A-250, was investigated. The effects of contact time, initial CN- concentration, pH, temperature, resin dosage, agitation speed, and particle size distribution on the removal of CN- were examined. The adsorption equilibrium data fitted the Langmuir isotherm very well. The maximum CN- adsorption capacity of Purolite A-250 was found to be 44 mg CN- g(-1) resin. More than 90% CN- adsorption was achieved for most CN- solutions (50, 100, and 200 mg CN- L(-1)) with a resin dose of 2 g L(-1). The equilibrium time was ∼20 min, optimum pH was 10.0-10.5, and optimum agitation speed was 150 rpm. An increase in adsorption of CN- with increasing resin dosage was observed. Adsorption of CN- by the resin was marginally affected (maximum 4% variation) within an environmentally relevant temperature range of 20-50 °C. Fixed-bed column (20.5 mm internal diameters) experiments were performed to investigate the effects of resin bed depth and influent flow rate on breakthrough behaviour. Breakthrough occurred in 5 min for 0.60 cm bed depth while it was 340 min for 5.40 cm bed depth. Adsorption capacity was 25.5 mg CN- g(-1) for 5 mL min(-1) flow rate and 3.9 mg CN- g(-1) for 20 mL min(-1) flow rate. The research has established that the resin can be effectively used for CN- removal from aqueous solutions.

Rare earth elements in sands collected from Southern California sea beaches.

Rare earth elements (REEs) are considered the limiting resources for advancing clean technologies and electronics. Because global REEs reserve is limited, non-conventional and secondary sources are being investigated for recovery. Here, we investigated wet and dry sand from seven Southern California beaches for sixteen REEs. These include five light REEs, two medium REEs, and nine heavy REEs, separated by their atomic weight. The mass of the magnetically separated compounds ranged from 15.19 to 129.91 g per kg of dry sand in the studied sea beaches in Southern California. The total REEs concentration ranged from 1168.1 to 6816.7 µg per kg of wet sand (dry sand basis) and 1474.7-7483.8 µg per kg of dry sand. Cerium (Ce) and Yttrium (Y) were the most prevalent REEs in these beaches ranging from 387.4 to 2241.1 µg kg-1 and 104.5-2302.3 µg kg-1 of sand respectively. This study found light REEs concentration accounted for 70-80% of total rare earth elements in the studied beaches. The concentrations of the analyzed REEs were significantly different (p < 0.05) from each other in the studied beaches. Additionally, Pearson correlation showed that the REEs were strongly correlated (r ≥ 0.83) with each other in the reported sea beaches, indicating a similar origin of the REEs. The dominant heavy metals in the studied samples were Vanadium (V), Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), and Strontium (Sr). Dominant minerals identified in sands were quartz, anorthite, ilmenite, and xenotime. All the beaches are lowly enriched with REEs, and any of the REEs caused no ecological risk or pollution. Similarly, no pollution/ecological risk was observed for the analyzed heavy metals. This study identified beach sand as a potential REEs source and demonstrated an easy separation of REEs containing magnetic compounds from sand.

Optimization of depth of filler media in horizontal flow constructed wetlands for maximizing removal rate coefficients of targeted pollutant(s).

Varying the depth of HFCW media causes differences in the redox status within the system, and hence the community structure and diversity of bacteria, affecting removal rates of different pollutants. The key functional microorganisms of CWs that remove contaminants belong to the phyla Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes. Secondary data of 111 HFCWs (1232 datasets) were analyzed to deduce the relationship between volumetric removal rate coefficients (KBOD, KTN, KTKN, and KTP) and depth. Equations of depth were derived in terms of rate coefficients using machine learning approach (MLR and SVR) (R2 = 0.85, 0.87 respectively). These equations were then used to find the optimum depth for pollutant(s) removal using Grey wolf optimization (GWO). The computed optimum depths were 1.48, 1.71, 1.91, 2.09, and 2.14 m for the removal of BOD, TKN, TN, TP, and combined nutrients, respectively, which were validated through primary data. This study would be helpful for optimal design of HFCWs.

Arsenic Contamination in Groundwater: Geochemical Basis of Treatment Technologies.

Arsenic (As) is abundant in the environment and can be found in both organic (e.g., methylated) and inorganic (e.g., arsenate and arsenite) forms. The source of As in the environment is attributed to both natural reactions and anthropogenic activities. As can also be released naturally to groundwater through As-bearing minerals including arsenopyrites, realgar, and orpiment. Similarly, agricultural and industrial activities have elevated As levels in groundwater. High levels of As in groundwater pose serious health risks and have been regulated in many developed and developing countries. In particular, the presence of inorganic forms of As in drinking water sources gained widespread attention due to their cellular and enzyme disruption activities. The research community has primarily focused on reviewing the natural occurrence and mobilization of As. Yet, As originating from anthropogenic activities, its mobility, and potential treatment techniques have not been covered. This review summarizes the origin, geochemistry, occurrence, mobilization, microbial interaction of natural and anthropogenic-As, and common remediation technologies for As removal from groundwater. In addition, As remediation methods are critically evaluated in terms of practical applicability at drinking water treatment plants, knowledge gaps, and future research needs. Finally, perspectives on As removal technologies and associated implementation limitations in developing countries and small communities are discussed.

Impacts of the COVID-19 pandemic on landfilling and recycling in the city of Fargo, North Dakota, USA.

The COVID-19 pandemic impacted different aspects of human lifestyle, including waste generation and management. The landfilled and recycled waste volume from the City of Fargo's annual solid waste report between 2019 and 2021 was critically analyzed to understand these impacts. The analysis showed a 4.5% increase in the residential waste volume in 2020 compared to 2019 and 2021, suggesting a pandemic-induced lockdown effect. The monthly residential waste volume was approximately 5-15% greater during the mandatory quarantine period (April - November 2020) than in 2019 and 2021. Commercial waste volume decreased by 12% during 2020 and then sharply increased in 2021 as commercial facilities reopened. The total recycling volume increased slightly by 2.5% in 2020 compared to 2019 and 2021. Cardboard recycling showed a 5.8% increase in 2020 from 2019 and a 13% increase in 2021 compared to 2020. This was presumably caused by the reliance on online shopping during the pandemic and becoming habituated to online shopping. The COVID-19 pandemic did not significantly impact other classes of recycled waste volumes. In summary, COVID-19 affected landfilling and recycling in different capacities in the City of Fargo. The data will contribute to the global understanding of the impact of COVID-19 on solid waste management practices.Implications: The COVID-19 pandemic impacted waste generation and management. In Fargo, USA, the monthly residential waste volume increased by up to 15% during the mandatory quarantine period in 2020 compared to the same period in 2019 and 2021. Conversely, the monthly commercial waste volume decreased during the mandatory quarantine period in 2020. The commercial waste volume increased in 2021 as commercial activities became normal. The cardboard recycling increased significantly because people became used to online shopping during the lockdown, and the practice continues. The findings will contribute to the global understanding of the impact of COVID-19 on solid waste management practices.

Iron nanoparticles coated with amphiphilic polysiloxane graft copolymers: dispersibility and contaminant treatability.

Amphiphilic polysiloxane graft copolymers (APGCs) were used as a delivery vehicle for nanoscale zerovalent iron (NZVI). The APGCs were designed to enable adsorption onto NZVI surfaces via carboxylic acid anchoring groups and polyethylene glycol (PEG) grafts were used to provide dispersibility in water. Degradation studies were conducted with trichloroethylene (TCE) as the model contaminant. TCE degradation rate with APGC-coated NZVI (CNZVI) was determined to be higher as compared to bare NZVI. The surface normalized degradation rate constants, k(SA) (Lm(2-) h(-1)), for TCE removal by CNZVI and bare NZVI ranged from 0.008 to 0.0760 to 007-0.016, respectively. Shelf life studies conducted over 12 months to access colloidal stability and 6 months to access TCE degradation indicated that colloidal stability and chemical reactivity of CNZVI remained more or less unchanged. The sedimentation characteristics of CNZVI under different ionic strength conditions (0-10 mM) did not change significantly. The steric nature of particle stabilization is expected to improve aquifer injection efficiency of the coated NZVI for groundwater remediation.

Montmorillonite-iron crosslinked alginate beads for aqueous phosphate removal.

Phosphate runoff from agriculture fields leads to eutrophication of the water bodies with devastating effects on the aquatic ecosystem. In this study, naturally occurring montmorillonite clay-incorporated iron crosslinked alginate biopolymer (MtIA) beads were synthesized and evaluated for aqueous phosphate removal. Batch experiment data showed an efficient phosphate removal (>99%) by the MtIA beads from solutions with different initial phosphate concentrations (1 and 5 mg PO43--P/L, and 100 µg PO43--P/L). The kinetic data fitted well into the pseudo-second-order kinetic model indicating chemisorption played an important role in phosphate removal. Based on analyses of results from the Elovich and intra-particulate diffusion models, phosphate removal by the MtIA beads was found to be chemisorption where both film diffusion and intra-particulate diffusion participated. The isotherm studies indicate that MtIA surfaces were heterogeneous, and the adsorption capacity of the beads calculated from Langmuir model was 48.7 mg PO43--P/g of dry beads which is ~2.3 times higher than values reported for other clay-metal-alginate beads. Electron microscopy (SEM-EDS) data from the beads showed a rough-textured surface which helped the beads achieve better contact with the phosphate ions. Fourier-transform infrared spectroscopy (FTIR) indicated that both iron and montmorillonite clay participated in crosslinking with the alginate chain. The MtIA beads worked effectively (>98% phosphate removal) over a wide pH range of 2-10 making it a robust adsorbent. The beads can potentially be used for phosphate recovery from eutrophic lakes, agricultural run-off, and municipal wastewater.

Comparative study of arsenic removal by iron-based nanomaterials: Potential candidates for field applications.

Graphene oxide supported magnetite (GM) and graphene oxide supported nanoscale zero-valent iron (GNZVI) nanohybrids were compared for arsenic removal at a wide pH range (3-9). While already published work reported high process efficiency for GM and GNZVI, they cannot be compared one-on-one given the non-identical experimental conditions. Each researcher team used different initial arsenic concentration, solution pH, and adsorbent dose. This study evaluated GM and GNZVI, bare magnetite (M), and bare nanoscale zero-valent iron (NZVI) for aqueous arsenic removal under similar experimental conditions. GNZVI worked more efficiently (>90%) in a wide pH range (3-9) for both As(III) and As(V), while GM was efficient (>90%) only at pH 3 for As(V) and As(III) removal was maximum of ~80% at pH 9. GNZVI also exhibited better aqueous dispersibility with a zeta potential of -21.02 mV compared to other adsorbents in this experiment. The arsenic removal based on normalized iron content indicated that the nanohybrids recorded improved arsenic removal compare to bare nanoparticles, and GNZVI worked the best. In NZVI-based nanomaterials (GNZVI and NZVI), electrostatic attraction played a limited role while surface complexation was dominant in removal of both the arsenic species. In case of M-based nanomaterials (GM and M), As(V) removal was controlled by electrostatic attraction while As(III) adsorption was ligand exchange and surface complexation. GNZVI has the potential for field application for drinking water arsenic removal.

GO-CeO2 nanohybrid for ultra-rapid fluoride removal from drinking water.

The presence of excess fluoride (F- > 1.5 mg/L) in drinking water affects more than 260 million people globally and leads to dental and skeletal fluorosis among other health problems. This study investigated fluoride removal by graphene oxide-ceria nanohybrid (GO-CeO2) and elucidated the mechanisms involved. The nanohybrid exhibited ultra-rapid kinetics for fluoride removal and the equilibrium (85% removal, 10 mg F-/L initial concentration) was achieved within 1 min which is one of the fastest kinetics for fluoride removal reported so far. Fluoride removal by the nanohybrid followed Langmuir isotherm with a maximum adsorption capacity of 8.61 mg/g at pH 6.5 and that increased to 16.07 mg/g when the pH was lowered to 4.0. Based on the experimental results and characterization data, we have postulated that both electrostatic interaction and surface complexation participated in the fluoride removal process. The O2- ions present in the CeO2 lattice were replaced by F- ions to make a coordination compound (complex). While both Ce4+ and Ce3+ were present in ceria nanoparticles (CeO2 NPs), Ce3+ participated in fluoride complexation. During fluoride removal by GO-CeO2, the GO sheets acted as electron mediators and help to reduce Ce4+ to Ce3+ at the CeO2 NPs-GO interface, and the additional Ce3+ enhanced fluoride removal by the nanohybrid.

Citric acid modified granular activated carbon for enhanced defluoridation.

Excess fluoride (F-, >1.5 mg F-/L) in drinking water affects >260 million people across the globe and leads to dental and skeletal fluorosis. In this study, commercially available granular activated carbon (GAC) was modified with 0.3 M citric acid to get citric acid modified GAC (CAGAC). Over 70% of fluoride was removed in the first 60 min by CAGAC, whereas unmodified GAC removed only 30%. There were negligible interferences by co-existing ions (NO3-, Cl-, HCO3-, SO42-, PO43-) and organic matters. Maximum adsorption capacity of CAGAC was two times (1.65 mg/g) that of unmodified GAC (0.88 mg/g). Dubinin-Radushkevich (D-R) isotherm described the experimental data well indicating that ion exchange was involved in fluoride removal. CAGAC worked effectively over a wide range of pH (2-10) even though the point-of-zero-charge (PZC) was 4.89, and so the removal was not controlled by electrostatic interaction alone; surface adsorption and intra-particle diffusion were the rate-determining processes.

Ultra-high arsenic adsorption by graphene oxide iron nanohybrid: Removal mechanisms and potential applications.

Iron (Fe)-based adsorbents have been promoted for aqueous arsenic adsorption because of their low cost and potential ease of scale-up in production. However, their field application is, so far, limited because of their low Fe use efficiency (i.e., not all available Fe is used), slow adsorption kinetics, and low adsorption capacity. In this study, we synthesized graphene oxide iron nanohybrid (GFeN) by decorating iron/iron oxide (Fe/FexOy) core-shell structured iron nanoparticles (FeNPs) on the surface of graphene oxide (GO) via a sol-gel process. The deposition of FeNPs on GO for the nanohybrid (GFeN) improves Fe use efficiency and arsenic mobility in the nanohybrid, thereby improving the arsenic removal capacity and kinetics. We achieved removal capacities of 306 mg/g for As(III) and 431 mg/g for As(V) using GFeN. Rapid reduction (>99% in <10 min) of As(III) and As(V) (initial concentration, C0 = 100 µg/L) was achieved with the nanohybrid (250 mg/L). There were no significant interferences by the coexisting anions and organic matters at environmentally relevant concentrations. Based on the experimental data, we have proposed that both electrostatic interaction and surface complexation contributed to ultra-high arsenic removal by GFeN. The GO sheets acted as the reservoirs for the electrons released during surface corrosion of the FeNPs and the electrons were transferred back to the FeNPs to rejuvenate the oxidized surface. The rejuvenated FeNP surface layer helped in additional arsenic removal.

The Barley HvWRKY6 Transcription Factor Is Required for Resistance Against Pyrenophora teres f. teres.

Barley is an important cereal crop worldwide because of its use in the brewing and distilling industry. However, adequate supplies of quality malting barley are threatened by global climate change due to drought in some regions and excess precipitation in others, which facilitates epidemics caused by fungal pathogens. The disease net form net blotch caused by the necrotrophic fungal pathogen Pyrenophora teres f. teres (Ptt) has emerged as a global threat to barley production and diverse populations of Ptt have shown a capacity to overcome deployed genetic resistances. The barley line CI5791 exhibits remarkably effective resistance to diverse Ptt isolates from around the world that maps to two major QTL on chromosomes 3H and 6H. To identify genes involved in this effective resistance, CI5791 seed were γ-irradiated and two mutants, designated CI5791-γ3 and CI5791-γ8, with compromised Ptt resistance were identified from an M2 population. Phenotyping of CI5791-γ3 and -γ8 × Heartland F2 populations showed three resistant to one susceptible segregation ratios and CI5791-γ3 × -γ8 F1 individuals were susceptible, thus these independent mutants are in a single allelic gene. Thirty-four homozygous mutant (susceptible) CI5791-γ3 × Heartland F2 individuals, representing 68 recombinant gametes, were genotyped via PCR genotype by sequencing. The data were used for single marker regression mapping placing the mutation on chromosome 3H within an approximate 75 cM interval encompassing the 3H CI5791 resistance QTL. Sequencing of the mutants and wild-type (WT) CI5791 genomic DNA following exome capture identified independent mutations of the HvWRKY6 transcription factor located on chromosome 3H at ∼50.7 cM, within the genetically delimited region. Post transcriptional gene silencing of HvWRKY6 in barley line CI5791 resulted in Ptt susceptibility, confirming that it functions in NFNB resistance, validating it as the gene underlying the mutant phenotypes. Allele analysis and transcript regulation of HvWRKY6 from resistant and susceptible lines revealed sequence identity and upregulation upon pathogen challenge in all genotypes analyzed, suggesting a conserved transcription factor is involved in the defense against the necrotrophic pathogen. We hypothesize that HvWRKY6 functions as a conserved signaling component of defense mechanisms that restricts Ptt growth in barley.

Rapid fractionation of natural organic matter in water using a novel solid-phase extraction technique.

This paper introduces a novel natural organic matter (NOM) fractionation technique using solid-phase extraction cartridges. The new technique requires only 6 hours of fractionation time, which is much faster than traditional fractionation techniques (24 hours). It uses three Bond Elute ENV cartridges (Varian, Inc., Lake Forest, California), one Strata X-C cartridge (Phenomenex, Torrance, California), and one Strata X-AW cartridge (Phenomenex) in series and was tested by using to fractionate NOM from Suwannee River, Georgia (SRNOM) and Red River, Minnesota (RRNOM). Hydrophobic acid was a major fraction and accounted for 66 to 70% and 36% of SRNOM and RRNOM, respectively. The NOM fractions obtained from the developed method were characterized using Fourier transformed infrared spectroscopy and 13C nuclear magnetic resonance. The acid fractions of SRNOM mainly consisted of carboxylic acids. An application of this new technique was demonstrated by using it to investigate the effectiveness of water treatment processes in removing different NOM fractions.

Incorporation of oxygen contribution by plant roots into classical dissolved oxygen deficit model for a subsurface flow treatment wetland.

It has been long established that plants play major roles in a treatment wetland. However, the role of plants has not been incorporated into wetland models. This study tries to incorporate wetland plants into a biochemical oxygen demand (BOD) model so that the relative contributions of the aerobic and anaerobic processes to meeting BOD can be quantitatively determined. The classical dissolved oxygen (DO) deficit model has been modified to simulate the DO curve for a field subsurface flow constructed wetland (SFCW) treating municipal wastewater. Sensitivities of model parameters have been analyzed. Based on the model it is predicted that in the SFCW under study about 64% BOD are degraded through aerobic routes and 36% is degraded anaerobically. While not exhaustive, this preliminary work should serve as a pointer for further research in wetland model development and to determine the values of some of the parameters used in the modified DO deficit and associated BOD model. It should be noted that nitrogen cycle and effects of temperature have not been addressed in these models for simplicity of model formulation. This paper should be read with this caveat in mind.

Remediation of alachlor and atrazine contaminated water with zero-valent iron nanoparticles.

Zero-valent iron nanoparticles (nZVI, diameter < 90 nm, specific surface area = 25 m(2) g(-1)) have been used under anoxic conditions for the remediation of pesticides alachlor and atrazine in water. While alachlor (10, 20, 40 mg L(-1)) was reduced by 92-96% within 72 h, no degradation of atrazine was observed. The alachlor degradation reaction was found to obey first-order kinetics very closely. The reaction rate (35.5 x 10(-3)-43.0 x 10(-3) h(-1)) increased with increasing alachlor concentration. The results are in conformity with other researchers who worked on these pesticides but mostly with micro ZVI and iron filings. This is for the first time that alachlor has been degraded under reductive environment using nZVI. The authors contend that nZVI may prove to be a simple method for on-site treatment of high concentration pesticide rinse water (100 mg L(-1)) and for use in flooring materials in pesticide filling and storage stations.

Assessment of molecularly imprinted polymers as phosphate sorbents.

Phosphorus (P) is a non-renewable natural resource which is used extensively in agriculture as a fertilizer. Phosphate (PO43-) rocks are mined to meet growing agricultural demands induced by rising global populations. Much of the P used in agricultural fields finds its way into surface waters where it permanently resides, leading to devastating effects on the aquatic ecosystem through eutrophication of the waterbodies. This research was aimed at developing a sorbent that can engender a P reuse cycle by utilizing eutrophic surface waters as viable P sources (mines). The goal was to develop a sorbent which can selectively recover low concentration (≤100 P µg L-1) typical of eutrophic waters. Molecularly imprinted polymers (MIPs) were identified as a potential technology for accomplishing this goal. Three MIPs were screened for viability by assessing their sorption capacities. After the initial screening, one MIP was selected for further studies. The selected MIP was found to have partial PO43- selectivity and tunable P sorption capacity. Adjusting the template:monomer ratio resulted in an increase in P sorption capacity from ∼11 to ∼28 mg PO43--P g-1, making this MIP competitive with existing technologies. The MIP was characterized to understand the polymer chemistry and mechanisms of P-removal. The possible mechanisms of aqueous P removal by the MIP were identified as selective chemical binding to the imprinted recognition sites and electrostatic attraction.

Adaption of microarray primers for iron transport and homeostasis gene expression in Pseudomonas fluorescens exposed to nano iron.

Modified protocols were adapted for PCR and culture based methods for the analysis of Pseudomonas fluorescens cells exposed to nanoscale zero-valent iron (NZVI) and iron (Fe) in bacterial growth nutrient media was determined by a modified atomic absorption spectrometric (AAS) analysis method. We adapted sets of microarray primers used to quantify gene expression of pvdS and a bacterioferritin-associated ferredoxin gene for use in real-time quantitative reverse transcription (qRT-PCR) analysis. pvdS is one of a cluster of genes regulating the synthesis of the siderophore pyoverdine that was also measured using chrome azrul S (CAS) plates. •The current protocol provides a detailed qRT-PCR method for quantifying genes involved in the acquisition and utilization of Fe in P. fluorescens cells exposed to NZVI.•The qRT-PCR results were independently corroborated with 2 culture based methods, growth curves and chrome azurol S (CAS) plate.•The modified AAS method was used to measure Fe in Tryptic Soy Broth (TSB) medium where sodium (Na) causes inference in iron measurement.