Integral Valorization of Posidonia oceanica Balls: An Abundant and Potential Biomass.

Posidonia oceanica balls (POB), a kind of seagrass, are a significant environmental issue since they are annually discharged onto beaches. Their current usefulness limits interest in their management and enhances the environmental problem. Therefore, in this research, the potential of this lignocellulosic biomass was studied from a holistic biorefinery point of view. To this end, an in-depth study was carried out to select the best pathway for the integral valorization of POBs. First, an autohydrolysis process was studied for the recovery of oligosaccharides. Then, a delignification stage was applied, where, in addition to studying different delignification methods, the influence of the autohydrolysis pre-treatment was also investigated. Finally, cellulose nanofibers (CNFs) were obtained through a chemo-mechanical treatment. The results showed that autohydrolysis not only improved the delignification process and its products, but also allowed the hemicelluloses to be valorized. Acetoformosolv delignification proved to be the most successful in terms of lignin and cellulose properties. However, alkaline delignification was able to extract the highest amount of lignin with low purity. CNFs were also successfully produced from bleached solids. Therefore, the potential of POB as a feedstock for a biorefinery was confirmed, and the pathway should be chosen according to the requirements of the desired end products.

Electrospun Cactus Mucilage/Poly(vinyl alcohol) Nanofibers as a Novel Wall Material for Dill Seed Essential Oil (Anethum graveolens L.) Encapsulation: Release and Antibacterial Activities.

This study aimed to create long-lasting carriers by producing electrospun nanofibers loaded with dill seed (Anethum graveolens L.) essential oil (DSEO), using cactus mucilage (CM) and poly(vinyl alcohol) (PVA). Continuous and uniform electrospun nanofibers with a diameter of 158 ± 18 to 230 ± 26 nm were successfully made from the CM/PVA blend solution and the CM/PVA/DSEO emulsion. Atomic force microscopy topographic images revealed that the electrospun nanofibers had a tubular morphology. The thermogravimetric curves of DSEO, CM, pure PVA, and electrospun nanofibers demonstrate that the polymers used and the essential oil have effective chemical interactions. The water contact angle results suggest that the manufactured nanofibers are hydrophilic. CM/PVA consistently achieves a remarkable encapsulation efficiency of 100% DSEO. The electrospun nanofibers enabled the controlled release of free and encapsulated DSEO, resulting in sustained long-term release. The agar disk diffusion technique was used to study the antimicrobial activity of electrospun nanofibers and nanofibers containing DSEO against Gram-positive and Gram-negative bacteria. With a minimum inhibitory concentration of 2.5 mg/mL and a minimum bactericidal concentration of 5 mg/mL, electrospun nanofibers containing DSEO demonstrated bacteriostatic and bactericidal activities against foodborne pathogenic bacteria (Staphylococcus aureus and Pseudomonas aeruginosa). The DSEO-loaded electrospun nanofibers derived from carbohydrates show promise as an active interior coating for use in biomedical and food packaging applications.

Biodegradable composite films based on mucilage from Opuntia ficus-indica (Cactaceae): Microstructural, functional and thermal properties.

This study evaluated the feasibility of using cactus mucilage (CM) to elaborate biobased composite films blended with styrene-butadiene rubber latex (SBL). The CM was extracted and precipitated with ethanol (CMET) and isopropanol (CMIS). Mucilage-based films were formulated using three levels of mucilage (4, 6, and 8 wt%). The microstructure, thickness, moisture content, density, water contact angle, water vapor permeability, film solubility, thermal stability, and toughness of mucilage films blended with SBL (SBL/CMET and SBL/CMIS) were measured. The properties of mucilage-based films varied systematically, depending on the concentration of mucilage. The addition of SBL to CM film produces compatible, hydrophobic, flexible, and stiffer films with low moisture contents and good barrier properties. The mucilage film incorporated with 6 wt% CMET and CMIS reached the highest Young's modulus of 1512 ± 21 and 1988 ± 55 MPa, respectively. The DSC of produced films reveals that the Tg of SBL/CMIS is lower than that of SBL/CMIS. The synthesized films were structurally stable at high temperatures. The biodegradability of the composite films buried in the ground shows that the produced films are 100 % biodegradable after 40 days. Thus, CM blended with SBL can benefit specific applications, especially food packaging.

Cross-Linked Carboxymethylcellulose Adsorbtion Membranes from Ziziphus lotus for the Removal of Organic Dye Pollutants

The goal of this study is to assess Ziziphus lotus's potential for producing carboxymethylcellulose adsorption membranes with the ability to adsorb methyl green from wastewaters by the revalorization of its cellulosic fraction. The cellulose from this feedstock was extracted by an alkaline process and TAPPI standard technique T 203 cm-99 and afterwards they were carboxymethylated. The obtained carboxymethylcelluloses were deeply characterized, being observed that the carboxymethylcellulose produced from the alkaline cellulose presented the higher solubility due to its lower crystallinity degree (53.31 vs. 59.4%) and its higher substitution degree (0.85 vs. 0.74). This carboxymethylcellulose was cross-linked with citric acid in an aqueous treatment in order to form an adsorption membrane. The citric acid provided rigidity to the membrane and although it was hydrophilic it was not soluble in water. By evaluating the potential of the produced membrane for the removal of pollutant dyes from wastewater, it was observed that the adsorption membrane prepared from the carboxymethylcellulose's produced from the Ziziphus lotus was able to remove 99% of the dye, methyl green, present in the wastewater. Thus, this work demonstrates the potential of the Ziziphus lotus for the production of a novel and cost-effective carboxymethylcellulose adsorption membrane with high capacity to treat wastewaters.

Cellulose Nanofibers from Schinus molle: Preparation and Characterization.

Schinus molle (SM) was investigated as a primary source of cellulose with the aim of discovering resources to generate cellulose nanofibers (CNF). The SM was put through a soda pulping process to purify the cellulose, and then, the fiber was treated with an enzymatic treatment. Then, a twin-screw extruder and/or masuko were utilized to help with fiber delamination during the nanofibrillation process. After the enzymatic treatment, the twin-screw extruder and masuko treatment give a yield of 49.6 and 50.2%, respectively. The optical and atomic force microscopy, morfi, and polymerization degrees of prepared cellulosic materials were established. The pulp fibers, collected following each treatment stage, demonstrated that fiber characteristics such as length and crystallinity varied according to the used treatment (mechanical or enzymatic treatment). Obviously, the enzymic treatment resulted in shorter fibers and an increased degree of polymerization. However, the CNF obtained after enzymatic and extrusion treatment was achieved, and it gave 19 nm as the arithmetic width and a Young's modulus of 8.63 GPa.

Assessment of heavy metal pollution in urban and peri-urban soil of Setif city (High Plains, eastern Algeria).

Heavy metal pollution is a challenging concern that threatens the soil environment and human health worldwide. The purpose of this work is to assess the heavy metals (Cr, Cu, Zn, and Pb) pollution in the urban and peri-urban soils in and around Setif city, eastern Algeria. The work combines chemical analysis of thirty-six soil samples, statistical valuation and interpretation of chemical data and pollution indices (geoaccumulation index, pollution index, and integrated pollution index) with thematic mapping. The average concentrations (in mg/kg) of Cd, Cr, Cu, Pb, and Zn were found < 0.02, 43.35, 43.75, 331.20, and 78.26 mg/kg, respectively. Compared with the French regulatory limits (AFNOR U44-041), Cd, Cr, and Cu still non-hazardous at Setif city scale; however, Zn and Pb concentrations are two to three times higher than the background values referred to the Chinese [Formula: see text] standard (GB15618-1995). The pollution indices indicate that Pb and Zn represent the highest threats among the studied pollutants and polluted wide areas of anthropogenic activities located respectively in the oldest district of the city, near the industrial zone and near uncontrolled landfill of domestic and industrial waste. Cu, Pb, and Zn originate seemly from vehicle emission, particles of brakes and tires, and industrial emissions. However, Cr distribution is uncorrelatable with anthropogenic sources. The Cr with an average concentration less than the background value derives seemly from animal feces and organic fertilizers. The integrated pollution index shows that the accumulation of heavy metals in the soils of Setif city from anthropogenic sources reached alarming levels that can disperse into the environment and threaten the human health. The urbanization and industrial development of Setif city are expected to grow and a subsequent heavy metal pollution will be rising prior issue. Corrective measures should be endeavored by the local authorities to mitigate the current environmental situation and a sustainable development plan for the city should be anticipated to guarantee optimal future environmental conditions.

Phenolic profile (HPLC-UV) analysis and biological activities of two organic extracts from Echinops spinosissimus Turra roots growing in Tunisia.

Echinops spinosissimus Turra subsp. roots was investigated, after extraction with two different solvents: ethanol and ethyl acetate, for its phenolic profile as well as biological activities. Echinops spinosissimus Turra subsp. spinosus roots ethanolic extract was characterized by the highest content of total polyphenols (19.3 mg GAE/100 g of DW). In addition, the phenolic profiles of the two studied extracts were analysed using HPLC-UV, where p-coumaric (8.59 mg/kg of DW) and cinnamic acids (4.68 mg/kg of DW) were detected as the most abundant phenolic acids, and kaempferol was the predominant flavonoids (30.37 mg/kg of DM) followed by quercetin and rutin in the ethanolic extract. While, only p-coumaric acid, epicatechin, kaempferol and quercetin were identified and quantified in ethyl acetate roots extract. All tested extracts exhibited an antimicrobial effect against Gram-positive and Gram-negative bacteria. These findings indicate that Echinops spinosissimus Turra subsp. spinosus roots can be regarded as a new source of edible oil having health benefits and nutritional properties.

Chemical modification of lignin derived from spent coffee grounds for methylene blue adsorption.

In this work, spent coffee grounds (SCG) were treated using sulfuric acid hydrolysis in order to isolate the sulfuric acid lignin (SAL). The reactivity of SAL was improved through phenolation and acetylation. Spectroscopic analysis showed that the isolated lignin is composed of GHS type and it was characterized by a high amount of (C-C) and ß-O-4 bonds. The thermal analysis showed that the phenolated sulfuric acid lignin (Ph-SAL) present higher thermal stability compared to SAL and acetylated sulfuric acid lignin. In addition, the phenolic hydroxyl group content increases from 2.99 to 9.49 mmol/g after phenolation. Moreover, a methylene blue (MB) adsorption test was established in order to find out the sorption capacity of different samples. The study showed that the adsorbed amount of dye increase after the chemical modification of SAL, especially after phenolation. The removal efficiency was enhanced after modification to reach 99.62% for Ph-SAL. The evaluation of the adsorption experimental data with the theoretical models of Langmuir and Freundlich showed that the best fitting was expressed by the Langmuir model for all samples. Finally, this study showed that lignin isolated from SCG can be simply and easily chemical modified and exhibits excellent adsorption ability towards cationic dyes (MB) in aqueous solutions. As a renewable, low-cost, and natural biomass material, lignin from SCG shows a promising practical and economical application of biomass in the field of wastewater purification.

Removal of barium and strontium from aqueous solution using zeolite 4A.

The adsorption efficiency of Sr(2+) and Ba(2+) from aqueous solutions by zeolite 4A was investigated. Adsorption studies were carried out both in single and binary component systems. The single ion equilibrium adsorption data were fitted to three isotherm models: Langmuir, Freundlich and Dubinin-Radushkevich. The Langmuir model represents the equilibrium data better than the Freundlich model in the studied initial metal concentration (0.3-25 mmol L(-1)) in both the single and binary component systems. The obtained RL (separation factor or Langmuir parameter) values were in the range of 0-1 indicating that Sr(2+) and Ba(2+) sorption were favorable. The obtained mean free energy value for adsorption of Ba(2+) and Sr(2+) was 8.45 kJ mol(-1) and 9.12 kJ mol(-1), respectively, indicating that both ions were uptaken through an ion exchange process. The maximum adsorption capacities (Qmax) were 2.25 mmol g(-1) and 2.34 mmol g(-1) for Ba(2+) and Sr(2+) ions, respectively. Also, the study of the competitive sorption of ions in the binary system showed that zeolite 4A preferentially adsorbs cations in the following order: Ba(2+) < Sr(2+).

Anodic oxidation of o-nitrophenol on BDD electrode: variable effects and mechanisms of degradation.

The electrochemical oxidation of pesticide, o-nitrophenol (ONP) as one kind of pesticide that is potentially dangerous and biorefractory, was studied by galvanostatic electrolysis using boron-doped diamond (BDD) as anode. The influence of several operating parameters, such as applied current density, supporting electrolyte, and initial pH value, was investigated. The best degradation occurred in the presence of Na2SO4 (0.05 M) as conductive electrolyte. After 8h, nearly complete degradation of o-nitrophenol was achieved (92%) using BDD electrodes at pH 3 and at current density equals 60 mA cm(-2). The decay kinetics of o-nitrophenol follows a pseudo-first-order reaction. Aromatic intermediates such as catechol, resorcinol, 1,2,4-trihydroxybenzene, hydroquinone and benzoquinone and carboxylic acids such as maleic glycolic, malonic, glyoxilic and oxalic, have been identified and followed during the ONP treatment by chromatographic techniques. From these anodic oxidation by-products, a plausible reaction sequence for ONP mineralization on BDD anodes is proposed.

Influence of physico-chemical treatment on the subsequent biological process treating paper industry wastewater.

The present paper presents the main results of the biodegradation study of paper industry wastewater through physico-chemical treatment. Indeed, around 60% of chemical oxygen demand (COD) removal can be achieved by electroflocculation treatment. Furthermore, a removal efficiency of the COD of almost 91% has been obtained by biological treatment, with activated amount of sludge for 24 h of culture. Concerning the physico-chemical pre-treatment of the untreated, filtered and electroflocculated rejection effluents, it has been investigated through the degradation curve of COD studies.

Ultrasonic activation of Heck type reactions in the presence of Aliquat-336.

Without phosphine and base, palladium catalysts such as PdCl(2), Pd(OAc)(2) and PdCl(2)(PhCN)(2) in water/DMF mixtures with Aliquat-336 proved to be excellent catalytic systems for Heck reactions involving several aryl bromides with styrene and acrylic compounds. Yields are remarkably improved under ultrasonic irradiation and the products show a high purity.