Nutrient Availability for Lactuca sativa Cultivated in an Amended Peatland: An Ionic Exchange Study

Few conservation strategies have been applied to cultivated peatland. This field study over one growth cycle of Lactuca sativa examined the effect of plant-based, high-C/N-ratio amendments in a real farming situation on peatland. Plant Root Simulator (PRS®) probes were used directly in the field to assess the impacts of incorporating Miscanthus x giganteus straw and Salix miyabeana chips on nutrient availability for lettuce. The results showed that lettuce yield decreased by 35% in the miscanthus straw treatment and by 14% in the willow chip treatment. In addition, the nitrogen flux rate was severely reduced during crop growth (75% reduction) and the plant N uptake index was much lower in the amended treatments than in the control. The phosphorus supply rate was also significantly lower (24% reduction) in the willow treatment. The influence of sampling zone was significant as well, with most macro-nutrients being depleted in the root zone and most micro-nutrients being mobilized. Additional work is needed to optimize the proposed conservation strategy and investigate the effects of consecutive years of soil amendment on different vegetable crops and in different types of cultivated peatlands to confirm and generalize the findings of this study. Future field studies should also explore the long-term carbon dynamics under plant-based, high-C/N-ratio amendments to determine if they can offset annual C losses.

Low-Impact Development (LID) in Coastal Watersheds: Infiltration Swale Pollutant Transfer in Transitional Tropical/Subtropical Climates

The control of runoff pollution is one of the advantages of low-impact development (LID) or sustainable drainage systems (SUDs), such as infiltration swales. Coastal areas may have characteristics that make the implementation of drainage systems difficult, such as sandy soils, shallow aquifers and flat terrains. The presence of contaminants was investigated through sampling and analysis of runoff, soil, and groundwater from a coastal region served by an infiltration swale located in southern Brazil. The swale proved to be very efficient in controlling the site’s urban drainage volumes even under intense tropical rainfall. Contaminants of Cd, Cu, Pb, Zn, Cr, Fe, Mn and Ni were identified at concentrations above the Brazilian regulatory limit (BRL) in both runoff and groundwater. Soil concentrations were low and within the regulatory limits, except for Cd. The soil was predominantly sandy, with neutral pH and low ionic exchange capacity, characteristic of coastal regions and not very suitable for contaminant retention. Thus, this kind of structure requires improvements for its use in similar environments, such as the use of adsorbents in soil swale to increase its retention capacity.

VOCs Photothermo-Catalytic Removal on MnOx-ZrO2 Catalysts

Solar photothermo-catalysis is a fascinating multi-catalytic approach for volatile organic compounds (VOCs) removal. In this work, we have explored the performance and the chemico-physical features of non-critical, noble, metal-free MnOx-ZrO2 mixed oxides. The structural, morphological, and optical characterizations of these materials pointed to as a low amount of ZrO2 favoured a good interaction and the ionic exchange between the Mn and the Zr ions. This favoured the redox properties of MnOx increasing the mobility of its oxygens that can participate in the VOCs oxidation through a Mars-van Krevelen mechanism. The further application of solar irradiation sped up the oxidation reactions promoting the VOCs total oxidation to CO2. The MnOx-5 wt.%ZrO2 sample showed, in the photothermo-catalytic tests, a toluene T90 (temperature of 90% of conversion) of 180 °C and an ethanol T90 conversion to CO2 of 156 °C, 36 °C, and 205 °C lower compared to the thermocatalytic tests, respectively. Finally, the same sample exhibited 84% toluene conversion and the best selectivity to CO2 in the ethanol removal after 5 h of solar irradiation at room temperature, a photoactivity similar to the most employed TiO2-based materials. The as-synthetized mixed oxide is promising for an improved sustainability in both catalyst design and environmental applications.

Improving Ionic Exchange Process of Potassium in Poor Soils by Bentonite

The current study was carried out to improve ionic exchange for potassium in sandy and gypsiferous soils to obtain an increase in absorption of potassium ions in NPK fertilizers, the improving process includes two stages; The first is adding NPK fertilizer with concentrations (0.020%, 0.040%, and 0.070%) by weight for two samples, the exchange potassium concentration was measured and notice the increasing from 124 ppm to 140 ppm in sandy soil and from156 ppm to 180 ppm in gypsiferous soil when using the highest concentration (0.070%), the second stage included adding grinded bentonite ore (10%, 20%,30%) by weight to the two samples after treated with NPK fertilizer in same concentrations above, potassium exchange increased to 340 ppm in sandy soil and to 450 ppm in gypsiferous soil by using NPK fertilizer and bentonite ore concentrate (0.070% & 30%) respectively.

Chemically modified polystyrene co-loaded with antimicrobial agents

A recent study showed that at least 50% of nosocomial infections are due to medical indwelling devices like surgical guides and prosthetics. This amounts to about 2 million patients affected a year. The reason for such statistics is the growth of microorganisms on the surfaces of the medical devices. There have been many attempts to create antimicrobial materials but most materials are unable to hold more than one antimicrobial agent without a secondary process. The study related to antimicrobial material with more than one type of agent is rarely found in literature. Hence, the objective of this project is to produce an antimicrobial material that can hold more than one antimicrobial agent without the need for a secondary process. The material is produced by sulfonating high impact polystyrene (HIPS) and attaching copper and silver ions. The optimum time of sulfonation of the HIPS was determined by the degree of sulfonation and ion exchange capacity. Then, the sulfonated HIPS were loaded with both copper and silver ions at different ratios. The 6-hour sample yielded the highest degree of sulfonation and ionic exchange capacity of 33.7% and 2.57 meq/g, respectively. In future work, the characterization of the 6-hour sulfonated HIPS sample loaded with copper and silver ions at different concentration ratios will be performed using TGA, DSC and FTIR spectroscopy. Lastly, the efficacy of the antimicrobial properties of the sulfonated HIPS will be tested using different bacterial strains.

CdS/PbSe Heterojunction Made via Chemical Bath Deposition and Ionic Exchange Processes to Develop Low-Cost and Scalable Devices

Complete optoelectronic devices present major difficulties that are caused by aqueous chemical deposition. In this work, a ITO/CdS/PbSe heterostructure was developed, depositing CdS over an ITO-coated substrate via a chemical bath deposition (CBD) technique. The next step involved the growth of a plumbonacrite film over CdS via CBD, where the film acted as a precursor film to be converted to PbSe via ion exchange. The characterization of each material involved in the heterostructure were as follows: the CdS thin films presented a hexagonal crystalline structure and bandgap of 2.42 eV; PbSe had a cubic structure and a bandgap of 0.34 eV. I vs. V measurements allowed the observation of the electrical behavior, which showed a change from an ohmic to diode response by applying a thermal annealing at 150 °C for 5 min. The forward bias of the diode response was in the order of 0.8 V, and the current-voltage characteristics were analyzed by using the modified Shockley model, obtaining an ideality factor of 2.47, being similar to a Schottky diode. Therefore, the reported process to synthesize an ITO/CdS/PbSe heterostructure by aqueous chemical methods was successful and could be used to develop optoelectronic devices.

Analysis of Ionic-Exchange of Selected Elements between Novel Nano-Hydroxyapatite-Silica Added Glass Ionomer Cement and Natural Teeth

One of the foremost missions in restorative dentistry is to discover a suitable material that can substitute lost and damaged tooth structure. To this date, most of the restorative materials utilized in dentistry are bio-inert. It is predicted that the addition of nano-HA-SiO2 to GIC matrix could produce a material with better ion-exchange between the restorative material and natural teeth. Therefore, the aim of the current study was to synthesize and investigate the transfer of specific elements (calcium, phosphorus, fluoride, silica, strontium, and alumina) between nano-hydroxyapatite-silica added GIC (nano-HA-SiO2-GIC) and human enamel and dentine. The novel nano-hydroxyapatite-silica (nano-HA-SiO2) was synthesized using one-pot sol-gel method and added to cGIC. Semi-quantitative energy dispersive X-ray (EDX) analysis was carried out to determine the elemental distribution of fluorine, silicon, phosphorus, calcium, strontium, and aluminum. Semi-quantitative energy dispersive X-ray (EDX) analysis was performed by collecting line-scans and dot-scans. The results of the current study seem to confirm the ionic exchange between nano-HA-SiO2-GIC and natural teeth, leading to the conclusion that increased remineralization may be possible with nano-HA-SiO2-GIC as compared to cGIC (Fuji IX).

Degradation of the o-phenylphenol fungicide in water by unconventional CeO2-WO3 photocatalysts

Background: Water pollution due to emerging contaminants such as pesticides, pharmaceutics and/or plasticizers, is a serious environmental problem strictly connected to the safety of human and ecosystem life. For this reason, the development of high-performing (photo)catalysts for water purification is crucial. Objective: In recent years, the synergistic effects in Advanced Oxidation Processes (AOPs) can perform better strategies to remove recalcitrant contaminants from water. In this contest, the (photo)catalytic activity of CeO2-WO2materials for the degradation of the orto-phenylphenol fungicide comparing the photocatalytic, the Fenton and the photo-Fenton-like processes, has been examined. Methods: The samples were synthetized through deposition-precipitation mediated with the hexamethylenetetramine (HMTA) surfactant. The chemico-physical properties of the materials were examined by Raman, UV-Vis Diffuse Reflectance (Uv-vis DRS) and X-Ray photoelectron (XPS) spectroscopies, N2 adsorption-desorption measurements and transmission electron microscopy (TEM). The (photo)catalytic measurements were made through a home-made photoreactor irradiated by a solar lamp. The degradation of the fungicide was measured by UV-vis spectroscopy. Results : An efficient heterojunction was formed between the CeO2 and the WO2 oxides, which provided a good degradation percentage of the pesticide (65%) employing the solar photo-Fenton-like reaction that was the best performing process among the three investigated AOPs. The addition of WO3on CeO2 facilitated the ionic exchange between the Ce and the W ions, boosting the redox properties of cerium oxide. Conclusions: The strong interaction between CeO2 and WO3 and the peculiar properties of this unconventional composite pave the way to its use as a promising material for water depollution.