Crops irrigated with reclaimed wastewater or grown in biosolids-amended soils may take up pharmaceuticals and personal care product ingredients (PPCPs) through their roots. The uptake pathways ...followed by PPCPs and the propensity for these compounds to bioaccumulate in food crops are still not well understood. In this critical review, we discuss processes expected to influence root uptake of PPCPs, evaluate current literature on uptake of PPCPs, assess models for predicting plant uptake of these compounds, and provide recommendations for future research, highlighting processes warranting study that hold promise for improving mechanistic understanding of plant uptake of PPCPs. We find that many processes that are expected to influence PPCP uptake and accumulation have received little study, particularly rhizosphere interactions, in planta transformations, and physicochemical properties beyond lipophilicity (as measured by K ow). Data gaps and discrepancies in methodology and reporting have so far hindered development of models that accurately predict plant uptake of PPCPs. Topics warranting investigation in future research include the influence of rhizosphere processes on uptake, determining mechanisms of uptake and accumulation, in planta transformations, the effects of PPCPs on plants, and the development of predictive models.
•The structural analysis of CS-TiO2 nanocomposite was elucidated by several techniques.•Synthesised CS-TiO2 nanocomposite was exploited in the waste water treatment.•Antimicrobial efficacy was ...evaluated against various microbial pathogens.
Chitosan, a natural polysaccharide widely used for various biological applications due to their potential benefits. Incorporation of biomaterials with semiconductor has been exploited for waste water treatment and biological applications due to their nanometric sizes and biocompatibility of chitosan. Chitosan-Titanium dioxide (CS-TiO2) nanocomposite was synthesized and their optical, structural, spectral, thermal, morphological and elemental analyses were carried out by several techniques. The particle size of the synthesized CS-TiO2 nanocomposite was around 90nm and has a crystalline structure with anatase phase of TiO2. The prepared nanocomposite acts as a photocatalyst for the removal of rhodamine B (RhB) and congo red (CR) dyes under visible light irradiation. The pseudo first order kinetics was derived according to Langmuir–Hinshelwood (L–H) model. The nanocomposite also proved to be an excellent antimicrobial agent against Gram-positive and Gram-negative bacteria; and also show activity against fungus. The antimicrobial activity of the CS-TiO2 nanocomposites exhibits a zone of inhibition ranged between 10.333±0.5773 and 25.667±1.5275 (mm).
Meeting stringent phosphorus (P) discharge standards remains one of the major challenges for wastewater utilities due to increased economic burdens associated with advanced (i.e., secondary, ...tertiary) treatment processes. In a trade-off between higher treatment cost and enhanced P removal, it is critical for the treatment plants to be able to select the most appropriate technology. To this end, established/emerging high performing P removal/recovery technologies (e.g., Modified University of Cape Towne process, Bardenpho process, membrane bioreactors, IFAS-EBPR, struvite recovery, tertiary reactive media filtration) were identified and full-scale treatment plant designs were developed. Using advanced mathematical modeling techniques, six different treatment configurations were evaluated in terms of performance and cost effectiveness ($/lb of P removed). Results show that the unit cost for P removal in different treatment alternatives range from $42.22 to $60.88 per lb of P removed. The MUCT BNR + tertiary reactive media filtration proved to be one of the most cost effective configurations ($44.04/lb P removed) delivering an effluent with total P (TP) concentration of only 0.05 mg/L. Although struvite recovery resulted in significant reduction in biosolids P, the decrease in effluent TP was not sufficient to meet very stringent discharge standards.
•IFAS-EBPR is the most cost-effective system ($42.25/lb-P removed; Peff = 0.82 mg/L).•MBR systems are the least cost-effective ($60.89/lb-P removed; Peff = 1.02 mg/L).•Tertiary filtration (high investment) is cost effective due to low Peff = 0.05 mg/L.•Side stream struvite recovery is not helpful in meeting stringent effluent TP limits.•Due to high capital and maintenance costs, MBR systems are not cost effective.
Samples from several wastewater treatment facilities in Wisconsin were screened for the presence of 21 antibiotic compounds. These facilities spanned a range of community size served (average daily ...flow from 0.0212 to 23.6 million gallons/day), secondary treatment processes, geographic locations across the state, and they discharged the treated effluents to both surface and ground waters (for ground water after a soil passage). A total of six antibiotic compounds were detected (1–5 compounds per site), including two sulfonamides (sulfamethazine, sulfamethoxazole), one tetracycline (tetracycline), fluoroquinolone (ciprofloxacin), macrolide (erythromycin-H
2O) and trimethoprim. The frequency of detection of antibiotics was in the following order: tetracycline and trimethoprim (80%)
>
sulfamethoxazole (70%)
>
erythromycin-H
2O (45%)
>
ciprofloxacin (40%)
>
sulfamethazine (10%). However, the soluble concentrations were in the parts-per-billion (ppb) range (≤
1.3 μg/L), and importantly were unaffected by the size of the wastewater treatment facility. The concentrations detected were within an order of magnitude of those reported for similar systems in Europe and Canada: they were within a factor of two in comparison to those reported for Canada but generally lower relative to those measured in wastewater systems in Europe. Only sulfamethoxazole and tetracycline were detected in groundwater monitoring wells adjacent to the treatment systems. Future intensive wastewater monitoring programs in Wisconsin may be limited to the six antibiotic compounds detected in this study.
Electrospun carbon nanofibers (CNF) with surface-anchored bimetallic gold–platinum nanoislands (CNFs@Au–Pt NIs) have been effectively developed by electrospinning and chemical reduction methods, and ...its enhanced trace-level hydrogen gas sensing characteristics at room temperature have been explored. Structural and morphological properties of the CNFs@platinum NIs (CNFs@Pt NIs) and CNFs@gold–platinum NIs (CNFs@Au–Pt NIs) have been characterized using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses, which showed the successful formation of bimetallic Au–Pt NIs homogeneously distributed over the surface of CNFs. The bimetallic Au–Pt NIs on CNFs provide superior hydrogen gas sensing properties toward wide range detection of hydrogen gas from 0.01 to 4% under ambient conditions. Desorption of hydrogen from the nanohybrids without any delay is possible as the chemisorbed hydrogen on Pt has been compensated with the integration of Au on CNFs leading to rapid response and recovery time. Adsorption kinetics studies indicate that the adsorption of hydrogen occurs on active Au–Pt bimetallic sites because of the work function differences leading to changes in the resistance. In situ Raman spectroscopic analysis revealed the interaction of hydrogen (H2) gas with the catalytic active NIs at room temperature, and a plausible mechanism has been proposed. This bimetallic catalyst functionalized CNFs can be considered as a potential candidate for the development of high-performance gas sensors with fast recovery and amplified response toward trace-level hydrogen gas for real time applications.
Solution chemistry (pH, ionic strength (I), and sorbate-to-sorbent ratio) effects on ciprofloxacin sorption to hydrous oxides of Al (HAO) and Fe (HFO) were investigated using macroscopic and ...spectroscopic analyses. Sorption to both HAO and HFO showed a strong pH-dependent behavior, following the fraction of zwitterionic species over the entire pH range studied. Increase in I from 0.01 to 0.5 M had an insignificant effect on the extent of ciprofloxacin sorption, and isotherms were well-described by the Langmuir model. HFO possessed a higher sorption capacity (0.066 mmol kg-1) than HAO (0.041 mmol kg-1). Ligand-promoted dissolution of hydrous oxides, more pronounced for HAO, was observed in the presence of ciprofloxacin, but at a fairly high initial concentration (0.5 mM). Attenuated total reflectance Fourier transform infrared spectroscopy analysis indicated that different types of ciprofloxacin surface complexes are formed with HAO and HFO; while a monodentate mononuclear complex (with −COO-) appears likely between ciprofloxacin and HAO, keto O and one O from COO- seem to be involved in the formation of a six-membered ring with Fe on the HFO surface. The study results are expected to increase our understanding of the environmental reactivity of fluoroquinolones, an important class of antimicrobial compounds.
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•Activated carbon cloth with varying meso-to-microporosity evaluated for electrosorption.•Both mesopores and micropores contributed to electrosorption via different ...mechanisms.•Micropores have higher electrosorption density than mesopores.•Electrosorption capacity decreases as ion radius increases.
Capacitive deionization (CDI) removes charged ions from aqueous solutions through entrapment in the electric double layer (EDL) when the porous electrodes are polarized. In this study, three types of activated carbon cloth (ACC) with different pore-size distributions were used to study the effect of pore characteristics on electrosorption during CDI. Removal of seven different monovalent ions was examined for each ACC in batch reactors under 5 different combinations of applied potential and ionic strength. Results show underlying sorption mechanisms in the meso- and micro-pores were different. Electrosorption in the mesopores is influenced by partially-distorted EDL caused by EDL overlapping. Sorption capacity increased with increasing applied potential or ionic strength as overlapping effects were reduced. In contrast, EDL in the microporous regions could be highly distorted resulting in enhanced sorption capacity, which cannot be adequately described using the classic EDL theories. Electrosorption density (i.e., sorption capacity normalized by pore volume) decreased as the mesoporosity-to-microporosity ratio increased. These results are in agreement with those obtained using mathematical modeling by other recent CDI studies. Charge efficiency values were between 20% and 40% and appear to be substantially influenced by Faradaic reactions and ion desorption from the electrode surfaces. These findings suggest that pore-size distribution of electrode materials, especially the meso/microporosity ratio, should be optimized for the removal of targeted ions by CDI and well characterized to conduct more precise CDI modeling.
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•Severe pretreatment conditions enhanced solubilization of carbohydrates.•Alkaline and alkaline hydrogen peroxide pretreatments enhanced methane yield.•Severe-acid pretreatment ...produced furan byproducts and inhibited biogas production.•Anaerobic microbes were more tolerable to HMF than to furfural.•Furfural inhibition reduced the potential for biogas production.
Dairy manure subjected to four pretreatments (acid, alkaline, sulfite (SPORL), alkaline hydrogen peroxide (AHP)) at high chemical dosages (termed severe conditions) were evaluated for enhancements in biogas production and inhibitory effects due to concomitant generation of furan byproducts. All four pretreatments enhanced solubilization of carbohydrates, but only alkaline and AHP resulted in higher methane yield (356 and 333 mL/g-VS, respectively) relative to moderate pretreatment conditions (311 and 261 mL/g-VS, respectively). Methane yield of severe-SPORL pretreatment (233 mL/g-VS) was greater than that of untreated manure (116 mL/g-VS), but lower than that of moderate-SPORL (353 mL/g-VS). Severe-acid pretreatment showed early termination in biogas production likely due to inhibitory effects of furfural and 5-hydroxymethyl furfural. Both experimental data and kinetic modeling indicated that severe-acid pretreatment led to degradation of carbohydrates to furfural, which reduced biogas production due to direct toxicity rather than competitive inhibitory effects. Pretreatment conditions (severity and byproduct levels) for dairy manure biomass may be optimized based on the current findings.
This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from choline chloride (ChCl) ...and four hydrogen-bond donors - acetic acid, lactic acid, levulinic acid and glycerol - were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkages in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.
The relative metal sorption ability of kraft and organosolv lignins was examined as a function of solution chemistry (pH, ionic strength (
I), sorbate-to-sorbent ratio) and reaction time. The surface ...charge characteristics and functional group composition of these lignins, especially kraft lignin, are favorable for metal sorption. Sorption of Cu and Cd increased with increasing pH and decreasing
I. Description of sorption isotherms required the more complex Sips equation, as compared to the simpler Langmuir and Freundlich formulations, indicative of the presence of binding sites with varying affinities on these lignin biosorbents. Sorption capacity varied in the following order: softwood organosolv lignin
<
hardwood organosolv lignin
<
hardwood kraft lignin
<
softwood kraft lignin with sorption maximum of 21.5, 40, 66.7, and 80.6
μmol/g, respectively, for Cu, and 8.2, 18.3, 25.2, and 28.7
μmol/g for Cd. Both Cu and Cd sorption kinetics were rapid with equilibrium levels attained within 80
min and faster uptake was noticed for Cu. Strong competitive effects exhibited by H
+ and Na
+ in limiting Cu and Cd sorption are suggestive of the occurrence of weak ion-exchange type interactions involving the carboxylic and phenolic functional groups. Additional pretreatment and surface modifications of these biosorbents might be required to increase metal sorption capacity and enhance their use in waster/wastewater treatment.
