Green Synthesis of Metallic Nanoparticles, Phytochemical Compounds and Antioxidant Activity Using Two Types of Algae Plants

Scientific studies have demonstrated that the vegetable material extracts act as potential precursors for the synthesis of nanomaterial using eco-friendly ways. Because the plant extracts contain various secondary metabolites, they act as reducing and stabilizing agents for the bioreduction reaction for synthesis of novel metallic nanoparticles. Herein, we describe the characteristics of different algae types, from different locations (Belgium and South Correa). Algae have important components, like chlorophyll and other plant pigments, omega-3 fatty acids and essential elements. Also, it has been demonstrated that algae provide a rich source of natural bioactive compounds with antibacterial and antioxidant properties. Another important aspect is the fact that algae represent a good wastewater treatment. In addition to the economic aspect, algae biomass is a source of biodiesel and offers an efficient way for nutrient consumption and provides aerobic bacteria with oxygen through photosynthesis. It is a low-cost technique for the removal of phosphorus, nitrogen and pathogens. We first characterized and compared quantitatively (polyphenols, flavonoids) and qualitatively (carbohydrates, alkaloids) the properties of two algae types extracts (green algae - Enteromorpha spp. and brown ones - Hizikia fusiforme). We then obtained and characterized the gold nanoparticles, formed using HAuCl4 (10-3 M) and algae sample extracts. The algae extracts, the green method for obtaining metallic nanoparticles (AuNP) and the nanoparticles investigated by UV-Vis spectroscopy, optical microscopy and SEM technique are shown in this research

Simulating Aquifer for Nitrate Ion Migration Processes in Soil

The objective of this study was to explore the removal of nitrate ions from groundwater by employing dynamic permeable reactive barriers (PRBs) with A400-nZVI. This research aimed to determine the parameters of the barrier and evaluate its overall capacity to retain nitrate ions during percolation with a potassium nitrate solution. The process involves obtaining zerovalent iron (nZVI) nanoparticles, which were synthesized and incorporated onto an anionic resin support material (A400) through the reduction reaction of ferrous ions with sodium borohydride (NaBH4). This is achieved by preparing a ferrous sulfate solution, contacting it with the ion exchange resin at various solid–liquid mass ratios and gradually adding sodium borohydride under continuous stirring in an oxygen-free environment to create the A400-nZVI barrier. The results of the study, focusing on the development of permeable reactive barriers composed of nano zero-valent iron and ion exchangers, highlight the significant potential of water treatment processes when appropriately sized. The research specifically assesses the effectiveness of NO3− removal by using the A400-nZVI permeable reactive barrier, conducting laboratory tests that simulate a naturally stratified aquifer with high nitrate contamination

Pollutants resulting from intensive poultry farming activities and their impact on the environment

Poultry farming activities can have a negative impact on the environment, namely: acidification (with NH3 mainly, H2S, NOx etc.); pollution of surface water and groundwater (with NO3- and NH4+); eutrophication (N, P); air pollution with NH3, N2O, NO, dust (PM10 and PM2.5), bioaerosols; increasing the greenhouse effect (CO2, CH4, N2O etc); drying (use of groundwater); smells, noise; pollution with heavy metals, pesticides and toxic substances; the spread of pathogens that are resistant to antibiotics; pollution of waters with residues of pharmaceutical products. As a result, in order to prevent or reduce the negative impact on the environment, in the production process it is necessary to use BREF/BAT techniques (Best Available Techniques). The activity of poultry farming must be done according to the best available techniques: the farming system, production halls and related facilities are designed and built according to the latest standards in the field; implicitly the consumption of raw materials, waste emissions, wastewater, air pollutants values being according to the legislation [1]

Phytoremediation of Wastewater Containing Lead and Manganese Ions Using Algae

Heavy metal pollution of water from industrial discharge is a major problem worldwide. Thus, the quality of the environment and human health are severely affected. Various conventional technologies have been applied for water treatment, but these can be expensive, especially for industrial water treatment, and may have limited treatment efficiencies. Phytoremediation is a method that is successfully applied to remove metal ions from wastewater. In addition to the high efficiency of the depollution treatment, this method has the advantages of a low cost of the operation and the existence of many plants that can be used. This article presents the results of using algae (Sargassum fusiforme and Enteromorpha prolifera) to treat water containing manganese and lead ions. It was observed that maximum efficiencies for wastewater treatment were obtained when was used the algae Enteromorpha prolifera for a 600 min contact time period. The highest wastewater treatment efficiency obtained using Sargassum fusiforme was 99.46%

Experiments in use of bentonite for energy recovery of used oils

The paper proposes the development of advanced, integrated technologies for materials with properties of adsorbents (e.g. bentonite), and the use of these material in processes of used oil recovery with remediation effect and energy recovery. The main objective is to replace diesel fuel, which is an expensive fuel, with revitalized oils for energy production. For these, laboratory experiments are required in two important directions. The first tests are related to the determination the optimum concentration of bentonite for removal of metals from used oil. The revitalization of the used oil leads to the protection of the combustion plant, to the increase of its lifetime and polluting emissions reduction. The second set of experiments relates to the determination of energy characteristics of used oil and revitalized used oil for energy production. Elemental analysis, lower heating value, viscosity, density and ash analysis were determined. Experimental test of combustion process on a small scale boiler has been done and the results shows an improved combustion process of revitalized oil compares with used oil and the decrease of the pollutant emissions

TiO2–Based Nanofibrous Membranes for Environmental Protection

Electrospinning is a unique technique that can be used to synthesize polymer and metal oxide nanofibers. In materials science, a very active field is represented by research on electrospun nanofibers. Fibrous membranes present fascinating features, such as a large surface area to volume ratio, excellent mechanical behavior, and a large surface area, which have many applications. Numerous techniques are available for the nanofiber’s synthesis, but electrospinning is presented as a simple process that allows one to obtain porous membranes containing smooth non-woven nanofibers. Titanium dioxide (TiO2) is the most widely used catalyst in photocatalytic degradation processes, it has advantages such as good photocatalytic activity, excellent chemical stability, low cost and non-toxicity. Thus, titanium dioxide (TiO2) is used in the synthesis of nanofibrous membranes that benefit experimental research by easy recyclability, excellent photocatalytic activity, high specific surface areas, and exhibiting stable hierarchical nanostructures. This article presents the synthesis of fiber membranes through the processes of electrospinning, coaxial electrospinning, electrospinning and electrospraying or electrospinning and precipitation. In addition to the synthesis of membranes, the recent progress of researchers emphasizing the efficiency of nanofiber photocatalytic membranes in removing pollutants from wastewater is also presented

Treatment of Wastewater Containing Nonsteroidal Anti-Inflammatory Drugs Using Activated Carbon Material

This study presents an adsorbent material (activated carbon) used in the treatment of wastewater with the role of removing ibuprofen, acetaminophen, diclofenac and ketoprofen pollutants. The wastewater treatment efficiencies of the activated carbon were systematically investigated using adsorption kinetics. The parameters studied were: pH (4 and 6 values of pH), initial concentration of wastewater (1, 5, and 10 mg/L), contact time (10 min), adsorbent quantity (0.1, 0.5, and 1 g), and isotherm models (Langmuir and Freundlich). The highest wastewater treatment efficiency was obtained at the 6 pH value. The determination of four anti-inflammatory drugs, frequently monitored in wastewater, was performed by a simple and fast method using the HPLC-technique-type DAD (diode array detector). The method was linear when the concentration ranged between 0.5 and 20 m/L for all compounds. The equilibrium concentration was obtained after 8 min. The octanol/water coefficient influenced the removal efficiency of the four drugs by the adsorbent material (activated carbon). The dose of activated carbon (0.1 to 1 g) significantly influenced the efficiency of wastewater treatment, which increased considerably when the dose of the adsorbent material increased. Using 1 g of the adsorbent material for the treatment of wastewater containing 1 mg/L initial concentration of pollutant compounds, the efficiencies were 98% for acetaminophen, 92% for diclofenac, 88% for ketoprofen and 96% for ibuprofen

Photodegradable organic pollutants from wastewater

Nowadays, environmental pollution is constantly increasing, and depollution is the most important challenge of the 21st century. This paper is a review of organic pollutants in wastewater that can be removed by the photocatalysis process. Also are presented specialized studies that demonstrate the removal of organic pollutants from wastewater and the experimental conditions necessary to obtain high treatment efficiencies. The important classes of pollutants in wastewater are hydrocarbons, halo compounds, carbonyl derivatives, alcohols, phenols, pesticides, surfactants, nitrogen containing compounds and dyes, and represent a major source of water pollution. These organic pollutants are photodegradable and can be easily removed by the photocatalysis process

Removal of Metals from Aqueous Solutions Using Sea Buckthorn Waste from Dietary Supplement Technology

The purpose of this study was to produce additional data for the valorization process of vegetable waste originating from dietary supplement technology. Two types of vegetable waste originating from different technological processes of sea buckthorn oil were used: vegetable waste from organic solvent extraction (P1) and vegetable waste from cold extraction (P2). Batch experiments evaluated the influence of pH, initial metal concentration, contact time, and Langmuir and Freundlich adsorption isotherms. The following pollutants—Cu, Cr, Co, Ni, Pb and Zn—from the wastewater were studied. The removal efficiency of metals from wastewater was evaluated at pH 3, 5 and 7. The highest metals removal efficiency was obtained at pH 5. It was observed that the Langmuir isotherm fits the adsorption process very well. Based on the results obtained, it can be concluded that vegetable waste resulting from the sea buckthorn oil industry could have potential applications for removing toxic metals from wastewater due to its high removal efficiency (>80%)

Multifunctional Membranes—A Versatile Approach for Emerging Pollutants Removal

This paper presents a comprehensive literature review surveying the most important polymer materials used for electrospinning processes and applied as membranes for the removal of emerging pollutants. Two types of processes integrate these membrane types: separation processes, where electrospun polymers act as a support for thin film composites (TFC), and adsorption as single or coupled processes (photo-catalysis, advanced oxidation, electrochemical), where a functionalization step is essential for the electrospun polymer to improve its properties. Emerging pollutants (EPs) released in the environment can be efficiently removed from water systems using electrospun membranes. The relevant results regarding removal efficiency, adsorption capacity, and the size and porosity of the membranes and fibers used for different EPs are described in detail