Second order nonlinear optical properties of poled films containing azobenzenes tailored with azulen-1-yl-pyridine.

Azo compounds, which are highly versatile molecules, have attracted a considerable attention both for their fundamental properties and for practical applications, especially in photonics. The conjugated azo-aromatic systems containing 4-(R-azulen-1-yl)-2,6-dimethyl-pyridine were investigated for their nonlinear optical properties. These molecules were embedded in polymethyl methacrylate (PMMA) matrix, and the obtained guest-host systems were processed into good optical quality thin film by spin coating technique. The dipolar moments of dissolved in PMMA molecules were oriented by applying a high DC electric field at a temperature close to the polymer glass transition temperature. The second - order nonlinear optical (NLO) properties of poled films were studied by the optical second harmonic generation technique (SHG). The poling kinetics, studied by in situ SHG as well as the measured second-order NLO susceptibilities of poled films are reported and discussed.

Innovative Collagen Based Biopolymers Tested as Fertilizers for Poor Soils Amendment.

Improving soil quality is of growing interest and, among optimal solutions, the reuse and recycling of biopolymers of pelt waste from the tannery industry have been proposed, one of them being for collagen hydrolysate with micronutrients and polymers incorporated, to be used as fertilizers for poor soils rehabilitation. As functionalization agents, polyacrylamide, starch and dolomite were included into biopolymer matrixes in order to enhance their specific efficiency. These fertilizers were adequately characterized for their physical-chemical properties, including nutrient content, and tested on three poor soils, while a fourth sample of normal soil was chosen for comparative purposes. These soils were also characterized for their texture and physical-chemical properties in order to establish the fertility state of the soils as a function of nutrient content. In this respect, a series of agrochemical tests were developed at laboratory scale, simulating real agriculture environments in a vegetation room, where a significant plant growth in height was observed for all the agro-hydrogels with nutrients encapsulated, and multiplication of the nodosities number was observed in the case of the soybean culture. The most significant effect was obtained in the case of the fertilizer functionalized with starch. Finally, the application dose of the organic fertilizers for specific culture plants was estimated, such as field cultures (cereals, corn), field vegetables, vineyards or fruit-growing plantations. These agro-collagen fertilizers are particularly recommended for amendment of field cereals and vegetables. The novelty of this study mainly consists of the recovery and recycling of the pelt waste as efficient fertilizers after their adequate functionalization with synthetic or natural biopolymers.

Green Synthesis of Advanced Carbon Materials Used as Precursors for Adsorbents Applied in Wastewater Treatment.

Huge amounts of vegetable waste, mainly resulting from the food industry, need large areas for storage, as they could cause hazardous environmental impact, leading to soil and water pollution or to CO2 emissions during accidental incineration. This work was aimed at recycling certain lignocellulosic waste (walnut shells, kernels of peach, apricot, and olive) to design advanced carbon material precursors (ACMP) to be used for obtaining nano-powders with high applicative potential in pollution abatement. Both waste and ACMP were characterized using proximate and elemental analysis, and by optical microscopy. Complex characterization of raw materials by FTIR, TGA-DTG, and SEM analysis were carried out. The ACMP were synthetized at 600-700 °C by innovative microwave heating technology which offers the advantages of lower energy consumption using 3.3 kW equipment at laboratory level. The ACMP ash < 3% and increased carbon content of 87% enabled the development of an extended pore network depending on degassing conditions during heating. TEM analysis revealed a well-developed porous structure of the synthesized ACMP carbonaceous materials. Due to the presence of oxygen functional groups, ACMPs exhibit adsorption properties highlighted by an iodine index of max. 500 mg/g and surface area BET of 300 m2/g, which make them attractive for removal of environmental pollutants such as dyes having molecule sizes below 2 nm and ions with pore dimensions below 1 nm, widely used industrially and found in underground waters (NO3-) or waste waters (SO42-).

Advanced Collagen-Based Composites as Fertilizers Obtained by Recycling Lime Pelts Waste Resulted during Leather Manufacture.

Recent trends in ecological agriculture practices are focused on finding optimal solutions for reuse and recycling of pelt waste from tannery industry. In this context, new collagen-based hydrogels with NPK nutrients encapsulated have been functionalized with synthetic and natural additives, including starch and dolomite, to be used as composite fertilizers. Possible interaction mechanisms are presented in case of each synthetic or natural additive, ranging from strong linkages as a result of esterification reactions until hydrogen bonds and ionic valences. Such interactions are responsible for nutrient release towards soil and plants. These fertilizers have been adequately characterized for their physical chemical and biochemical properties, including nutrient content, and tested on three Greek poor soils and one Romanian normal soil samples. A series of agrochemical tests have been developed by evaluation of uptake and leaching of nutrients on mixtures of sand and soils. It was observed that the clay soil exhibits a higher adsorption capacity than the loam soil for most of nutrients leached from the composite fertilizers tested, with this being correlated with a slower control release towards cultivated plants, thus assuring efficiency of these collagen-based composite fertilizers. The most significant effect was obtained in the case of collagen-based fertilizer functionalized with starch.

Collagen-Based Hydrogels Composites from Hide Waste to Produce Smart Fertilizers.

The study aims at reusing and recycling the protein hide waste from the leather industry in ecological conditions by elaborating an innovative procedure in order to obtain a collagen matrix functionalized with nitrogen, phosphorus, and potassium (NPK) nutrients to be used for preparing smart fertilizers. This is an interdisciplinary approach, as it starts from hide waste raw material as a critical industrial waste, which is then subjected to several technological steps by selection of optimal processing parameters, followed by product fabrication at the laboratory, and next scales to the industrial pilot plant to obtain novel agro-hydrogels. In this context, the technology scheme for collagen hydrolysate with encapsulated nutrients was proposed and the process parameters were optimized by functionalization of agro-hydrogels with various natural and synthetic polymers, such as polyacrylamide, poly(sodium 4-styrenesulfonate-co-glycidyl methacrylate) copolymer, starch or dolomite. Based on the laboratory experiments, a pilot plant was constructed and tested. Taking as reference the collagen hydrolysate with encapsulated nutrients, the new fertilizers were adequately characterized by chemical analysis, determination of biodegradability and the degree of release of oxidable compounds in water. Based on the biodegradation mechanism and kinetic analysis of oxidable compounds release, adequate arguments are evidenced to demonstrate that these fertilizers can be applied for amendment of poor agricultural soils.