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    Phosphorus Removal from Dirty Farmyard Water by Activated Anaerobic-Digestion-Derived Biochar
    (American Chemical Society, 2022-12-05) Zhang, Chen; Sun, Shuzhuang; Xu, Shaojun; Johnston, Chris; Wu, Chunfei
    The management of anaerobic digestate is important to realize the value of the waste and enhance the whole system sustainability of anaerobic digestion. In this study, the phosphorus treatment of dirty irrigation water by biochar samples derived from digestate of anaerobic digestion were investigated. The biochars were further activated by steam activation with different duration time and KOH activation with different introducing ratios; the textural properties of biochars were optimized after activation from the aspect of biochar characterization. Notably, AD-N2 demonstrates a remarkable adsorption effect of phosphorus, with an adsorption efficiency of 8.99 mg g−1. Besides the effect of biochar dosage on phosphorus removal, adsorption kinetics and thermodynamic isotherms are studied. According to the adsorption kinetics, the adsorption of phosphorus from dirty water fits the Elovich equation (R2 = 0.95). Furthermore, the thermodynamic isotherm results illustrate the process of phosphorus removal by biochar is endothermic (ΔH0 = 17.93 kJ mol−1) and spontaneous (ΔS = 96.24 J mol−1 K−1). Therefore, this work suggests a promising solution to phosphorus-related environmental challenges in industry and agriculture.
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    Rhamnolipids Mediate the Effects of a Gastropod Grazer in Regards to Carbon–Nitrogen Stoichiometry of Intertidal Microbial Biofilms
    (MDPI, 2022-12-12) Gill, Stephanie P.; Kregting, Louise; Banat, Ibrahim M.; Arnscheidt, Joerg; Hunter, Billy
    Microbial biofilms have co-evolved with grazing animals, such as gastropods, to develop mutually beneficial relationships. Although microbial biofilms demonstrate resilience and resistance to chemical exposure, pre-existing relationships can be negatively affected by chemical input. In this study, we determined how the grazer, Littorina littorea (common periwinkle sea snail), and a biological surfactant (rhamnolipid) interact on a phototrophic marine biofilm. Biofilms were cultured in 32 twenty-liter buckets at the Queen’s University Marine Laboratory in Portaferry, Northern Ireland on clay tiles that were either exposed to 150 ppm of a rhamnolipid solution or that had no chemical exposure. L. littorea were added into half of the buckets, and biofilms were developed over 14 days. Biofilms exposed to grazing alone demonstrated high tolerance to the disturbance, while those growing on rhamnolipid-exposed substrate demonstrated resistance but experienced slight declines in carbon and stoichiometric ratios. However, when exposed to both, biofilms had significant decreases in stoichiometry and declined in productivity and respiration. This is problematic, as continuing marine pollution increases the likelihood that biofilms will be exposed to combinations of stressors and disturbances. Loss of biofilm productivity within these areas could lead to the loss of an important food source and nutrient cycler within the marine ecosystem.
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    Impact of cooking on vitamin D-3 and 25(OH)D-3 content of pork products
    (Elsevier, 2022-08-02) Neill, H.R.; Gill, C.I.R.; McDonald, E.J.; McRoberts, W. Colin; Loy, Ruth A.; Pourshahidi, L.K.
    Little is known regarding the impact of cooking on vitamin D content in pork, despite meat being a major contributor to vitamin D intakes. This paper investigated the effect of household cooking (pan-fry/roast/grill/sous-vide/sauté), on the vitamin D3 and 25-hydroxyvitamin D3 (25(OH)D3) concentration/retention in pork loin, mince and sausages. We hypothesised that vitamin D concentrations would be higher in cooked vs raw pork, and retention would differ between products. Cooking significantly increased vitamin D3 (+49 %) and 25(OH)D3 (+33 %) concentrations. All cooked loin vitamin D3 concentrations were significantly lower than mince/sausage. Vitamin D3 retention was > 100 % for all samples (102–135 %), except sauté mince (99 %) which still did not differ significantly from 100 % retention. Sous-vide cooking resulted in the highest vitamin D3 retention (135 %). Likely owing to water/fat loss, household cooking of pork results in favourable retention of vitamin D3 and 25(OH)D3. The type of pork product has greater influence than cooking method.
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    The effect of biochar and acid activated biochar on ammonia emissions during manure storage
    (Elsevier, 2022-12-05) Baral, Khagendra; McIlroy, John; Lyons, Gary A.; Johnston, Christopher
    Animal manure contains valuable plant nutrients which need to be stored until field application. A significant proportion of slurry nitrogen is volatilized in the form of ammonia (NH3) during storage. This impacts human health, biodiversity, air and water quality and thus urgent action is needed to reduce NH3 emissions. In this experiment, we evaluated the NH3 emission mitigation potential of biochars derived from miscanthus (MB) and solid separated anaerobic digestate (DB), and orthophosphoric acid activated MB (AMB) and DB (ADB) as well as lightweight expanded clay aggregate (LECA) during four months of liquid manure storage. A slurry without amendment was included as a control (Ctrl). Acid activated and non-activated biochars were applied on top of the slurry maintaining a 7 mm thick surface layer, while LECA was applied in a 2 cm thick layer. NH3 emissions were measured by photoacoustic analyzer. In comparison to Ctrl, acid activated biochar decreased (p < 0.05) NH3 emissions during the slurry storage. Activated biochar reduced the emissions by 37–51% within the first month of slurry storage and achieved a 25–28% emissions reduction efficiency throughout the four month period due to the reduction in emission mitigation efficiency as the storage period progressed. LECA reduced NH3 emissions by 21% during storage. Losses of NH3 as a percentage of total ammoniacal N were 29–31% for activated biochars, 35–39% for non-activated biochars and 33% for LECA. In conclusion, acid activated biochars and LECA could be good floating-covers to mitigate NH3 emissions during manure storage, but activated biochars may have better mitigation potential than LECA.
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    Application of metal oxide semiconductor for detection of ammonia emissions from agricultural sources
    (Elsevier, 2022-11-21) Molleman, Bastiaan; Alessi, Enrico; Krol, Dominika; Morton, Phoebe; Daly, Karen
    Agricultural emissions of ammonia (NH3) reduce air quality and biodiversity. Measuring the effectiveness of mitigations measures requires rapid monitoring tools, however, conventional methods are labour intensive and costly. This study evaluated the performance of a prototype metal oxide semiconductor (MOS) gas sensor for monitoring NH3. Conventional methods were used to calibrate sensor conductance. The metal oxide semiconductor (MOS) gas sensor was calibrated against NH3 released from a 0.1 M phosphate buffer spiked with ammonium chloride and NH3 released from recently spread cattle slurry. Field measurements using the MOS sensor were compared with values measuring a Bruker Open Path Air Monitoring System. Sensor conductance and NH3 concentration were described using single site Langmuir adsorption model. Field calibrations suggest a higher detection limit above 0.1 ppm and coefficients of determination were 0.93 and 0.89 for sensors 1 and 2, respectively. For prototypes deployed under field conditions, sensitivities of 2.2 and 2.4 with nonlinearity constants of 0.53 and 0.51, were found for sensor 1 and 3 respectively. Average R2 values were 0.88 for sensor 1 and 0.92 for sensor 3. The calibrations were used to calculate NH3 concentrations from slurry emissions using MOS sensor conductance. NH3 concentrations between 0.2 and 1 ppm, were measured with standard deviation of 20% of verified concentrations. The MOS sensor is sensitive enough to detect NH3 emission from agricultural sources with concentrations above 0.2 ppm. Low power and cost of MOS sensors are an advantage over existing techniques.