Vertical differentiation of pedogenic iron forms – a key of hydromorphic soil profile development

This paper focuses on the vertical distribution and characterisation of pedogenic iron forms in a Gleysol- Histosol transect developed in a marshy area in the Danube-Tisza Interfluve, Hungary. Four soil profiles were investigated along a series of increasing waterlogging and spatial and temporal patterns of hydromorphic pedofeatures (characteristics of pedogenic iron forms) were recorded. Frequent and wide-range redox potential (Eh) changes caused the emergence of many types of redoximorphic iron features, including mottles, plaques and nodules. The forms of these features depended on the micro-environments determined by the vertical position in the soil profile and the presence of plant roots. The greatest iron enrichment occurred in the zone of most intensive and widest-range redox fluctuations. Increasing water saturation resulted the extension of gleyic pattern due to the existence of permanent reduction. Most of the features also showed annual variations during the varying periods of water saturation and aeration.

Foliar Application of Nano, Chelated, and Conventional Iron Forms Enhanced Growth, Nutritional Status, Fruiting Aspects, and Fruit Quality of Washington Navel Orange Trees (Citrus sinensis L. Osbeck)

Iron (Fe) is required for most metabolic processes, including DNA synthesis, respiration, photosynthesis, and chlorophyll biosynthesis; however, Fe deficiency is common in arid regions, necessitating additional research to determine the most efficient form of absorbance. Nano-fertilizers have characteristics that are not found in their traditional equivalents. This research was implemented on Washington navel orange trees (Citrus sinensis L. Osbeck) to investigate the effect of three iron forms—nano (Fe-NPs), sulfate (FeSO4), and chelated (Fe-chelated)—as a foliar spray on the growth, fruiting aspects, and nutritional status of these trees compared to control. The highest values of the tested parameters were reported when the highest Fe-NPs level and the highest Fe-chelated (EDTA) rate were used. Results obtained here showed that the spraying of the Washington navel orange trees grown under similar environmental conditions and horticulture practices adopted in the current experiment with Fe-NPs (nanoform) and/or Fe-chelated (EDTA) at 0.1% is a beneficial application for enhancing vegetative growth, flower set, tree nutritional status, and fruit production and quality. Application of Fe-NPs and Fe-chelated (EDTA, 0.1%) increased yield by 32.0% and 25% and total soluble solids (TSS) by 18.5% and 17.0%, respectively, compared with control. Spraying Washington navel orange trees with nano and chelated iron could be considered a significant way to improve vegetative growth, fruit production, quality, and nutritional status while also being environmentally preferred in the arid regions.

Iron Forms Fe(II) and Fe(III) Determination in Pre-Roman Iron Age Archaeological Pottery as a New Tool in Archaeometry

This article presents studies on iron speciation in the pottery obtained from archaeological sites. The determination of iron forms Fe(II) and Fe(III) has been provided by a very simple test that is available for routine analysis involving the technique of molecular absorption spectrophotometry (UV–Vis) in the acid leachable fraction of pottery. The elemental composition of the acid leachable fraction has been determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Additionally, the total concentration of the selected elements has been determined by X-ray fluorescence spectrometry with energy dispersion (EDXRF). The results of the iron forms’ determinations in archaeological pottery samples have been applied in the archaeometric studies on the potential recognition of the pottery production technology, definitely going beyond the traditional analysis of the pottery colour.

Improvement of Solar Photo-Fenton by Extracts of Amazonian Fruits for the Degradation of Pharmaceuticals in Municipal Wastewater

Extracts of copoazu (Theobroma gramdiflorum), canangucha (Maurita Flexuosa), and coffee (coffea arabica) were explored as enhancers of the solar photo-Fenton process to eliminate acetaminophen, sulfamethoxazole, carbamazepine, and diclofenac. The process performance, at pH 6.2 and 5 mg L− 1 of iron without the extracts, has a very limited action (~ 35% of the pollutants degradation at 90 min of treatment) due to the iron precipitation. Interestingly, the extracts addition increased the soluble iron forms but only copoazu extract improved the pollutants degradation (~ 95% of elimination at 90 min of the process action). The copoazu extract acted as a natural complexing agent, maintaining the soluble iron up to 2 mg L− 1 even after 90 min, and consequently enhancing the pollutants degradation. The effect of copoazu extract dose on the process performance was also assessed, finding that an iron: copoazu extract molar ratio equal to 1:0.16 was the most favorable condition. Then, the process improved by copoazu extract was applied to municipal wastewater. Remarkably, the process led to ~ 90% of total pharmaceuticals degradation at 20 min of treatment. This work evidences the feasibility of amazonian fruits extracts to improve the solar photo-Fenton process to degrade pharmaceuticals in aqueous matrices at near-neutral pH.

Iron Speciation and Physiological Analysis Indicate that Synechococcus sp. PCC 7002 Reduces Amorphous and Crystalline Iron Forms in Synthetic Seawater Medium

Cyanobacteria have high iron requirements due to iron-rich photosynthetic machineries. Despite the high concentrations of iron in the Earth’s crust, iron is limiting in many marine environments due to iron’s low solubility. Oxic conditions leave a large portion of the ocean’s iron pool unavailable for biotic uptake, and so the physiochemical properties of iron are hugely important for iron’s bioavailability. Our study is the first to investigate the effect of iron source on iron internalization and extracellular reduction by Synechococcus sp. PCC 7002. The results indicated that the amorphous iron hydrolysis species produced by FeCl3 better support growth in Synechococcus through more efficient iron internalization and a larger degree of extracellular reduction of iron than the crystalline FeO(OH). An analysis of dissolved iron (II) indicated that biogenic reduction took place in cultures of Synechococcus grown on both FeCl3 and FeO(OH).