Principal Functional Groups Research Articles

Characterization of biodegradable films based on carboxymethyl cellulose and citrus pectin films enriched with bee bread oil and thyme oil

Films based on polysaccharides (e.g., cellulose esters, pectin) are often utilized as bio-packaging for food products. In this study, films were developed by casting method using carboxymethyl cellulose (CMC), pectin (P), and glycerol incorporated with two essential oils (EOs), bee bread oil (BBO) and thyme oil (TO) in different concentrations (1, 2, and 3%). The formulated films were described in terms of physicochemical properties, as well as through FT-IR spectroscopy, morphological, and thermogravimetric analysis, and with a focus on biodegradation degree. The addition of BBO to CMC films enhanced mechanical properties (77.22–81.96 MPa for tensile strength and 380.5–629.5 MPa for Young's modulus) and reduced barrier characteristics (0.46–0.74 g × mm/kPa × h × m2 and 0.69–0.84 cc × mm/m2 × atm × day for water vapor and oxygen permeabilities, respectively). The EOs decreased the films' opacity and increased their transparency. Considerably, films incorporating 2% and 3% of BBO and TO were completely degraded after 20 days of burial. Furthermore, principal functional groups and interaction between polymers and EOs were observed by FT-IR spectroscopy and morphological analysis of films.

Effect of cement slurry filtrate on methane hydrate stability during deepwater cementing operations

Whether the hydrate layer is stabilized during deepwater cementing operations has a direct impact on the safety of the cementing process and the quality of the cementing. When the cement slurry enters the annular space and waits for solidification, it will be extruded to produce filtrate under the action of formation temperature and pressure. Moreover, the inorganic ions and organic matter contained in the filtrate may penetrate into the formation. However, whether these processes have an effect on the stability of the hydrate layer is not clear at present.In this paper, we initially developed a methane hydrate generation system, termed the water-quartz sand-methane system. This system efficiently produces methane hydrate within a short time and ensures a uniform distribution of the gas-solid phase, which is highly suitable for further research into methane hydrate stability. Subsequently, the primary constituents of the cement slurry filtrate and the principal functional groups of the cement additive were identified. Furthermore, enhancements were made to the existing formula for quantifying methane gas alteration. Additionally, a hydrate testing experimental system was employed to circulate a solution comprising the primary constituents of the cement slurry filtrate over the methane hydrate surface. Ultimately, utilizing the amount of change in the volume of methane gas in the cyclic process as a criterion to evaluate the impact of various components of the cement slurry filtrate on methane hydrate stability, an investigation into the effect of the cement slurry filtrate on methane hydrate stability was conducted. It was confirmed that Ca2+, Na+, Cl− ions within the cement slurry filtrate, along with the pH value, minimally influence methane hydrate stability. Conversely, the cement additive exhibits a discernible disruptive effect on methane hydrate stability, with the retarder demonstrating the most pronounced impact when mass fractions are equated.This study suggests that the adverse effects of amide and carboxyl groups on hydrate stability must be considered in the selection of additives for deepwater cementing slurries. The findings offer guidance for the research and development of additives for deepwater cementing slurries and establish a theoretical foundation for studying cementing slurry systems in hydrate formations.

Mitigation of zearalenone in vitro using probiotic strains

Zearalenone (ZEN), a hazardous secondary metabolite produced by Fusarium, possesses an estrogen-like structure that triggers early pubertal changes and estrogenic diseases in animals. This research explores how physically treated Lactobacillus strains adsorb ZEN. According to the findings, four Lactobacillus strains—L1 (Lactobacillus plantae), L2 (Lactobacillus plantarum), L8 (Lactobacillus paracasei), and L9 (Lactobacillus acidophilus)—demonstrated evidence of ZEN adsorption and degradation in a 0.9% NaCl solution. Their activity ranged from 73% to 80% after 1 h, increasing to 86%–90% after 24 h. Among them, L9 exhibited the highest percentage of ZEN adsorption (90.39%), followed by L2 (88.68%), L1 (86.49%), and L8 (86.14%). Furthermore, LCMS/MS analysis revealed the involvement of the L8 and L1 strains in the degradation of ZEN into zearalenone sulfate (m/z 397.06) and α-zearalanol (α-ZAL m/z 321.13). According to FTIR analyses, the principal functional groups such as amides (C–N, CO), carboxyls (O–H, CO, or C–O), and alcohols (O–H) remained unaltered following ZEN adsorption, in comparison to heat-treated cells. These findings suggest that ZEN is hydrophobically adsorbed by Lactobacillus strains. Lactobacillus strains exhibited better ZEN reduction 87.27% and 91.7% after heat treatment, leading to modified bacterial cell shapes. Therefore, these four Lactobacillus strains could be considered natural adsorbents for removing ZEN from food products and feedstuffs.

Comparing Ant Assemblages and Functional Groups across Urban Habitats and Seasons in an East Asia Monsoon Climate Area.

China's East Asia monsoon zone is undergoing rapid land-use conversion and urbanization. Safeguarding remaining biodiversity requires reducing, mitigating, and/or eliminating the negative impacts of human-induced landscape modification. In this study, we sampled ground-dwelling ants at 40 plots over 12 continuous months in a suburban area in southwestern China to examine whether and how vegetation composition and habitat fragmentation affected species richness and assemblage composition for the general ant community and, specifically, for principal functional groups (including Opportunists and Generalized Myrmicinae). Warmer seasons were associated with a higher capture rate for all functional groups. Patterns of ant species richness among Opportunists were more sensitive to vegetation and fragmentation than for Generalized Myrmicinae, and these effects generally varied with season. Patterns of ant assemblage composition for Opportunists were exclusively sensitive to vegetation, whereas Generalized Myrmicinae were sensitive to both vegetation and fragmentation with variation among seasons. Overall, our findings highlight the important role of seasonality, vegetation composition, and habitat fragmentation in mediating the impacts of human-induced landscape modification on urbanized ant communities, which make an essential functional contribution to biodiversity in the East Asia monsoon zone.

Sustainable Synthesis of Highly Functionalized Activated Carbon using Plasma Technology.

Surface functionalized activated carbon (SFAC) has been used for several applications, including adsorption, catalysis and energy storage materials. Existing chemical and physical activation methods for surface functionalization are mostly identified as expensive, inefficient, and non-green methods. Plasma, known as the fourth state of matter, has recently been recognized as an attractive and sustainable method for introducing a higher degree of surface functionality to activated carbon. It also improves the bulk chemical structure and the properties of SFAC. The surface functionalization process is governed by discharge gas, discharge source, discharge efficiency and discharge time. The majority of researchers have utilized oxygen plasma as the discharge gas. However, ammonia, carbon dioxide, atmospheric air, specific gases such as chlorine and hydrogen sulfide, and neutral gases such as nitrogen and argon have also been used as the discharge gas. These plasma activations were conducted under different power conditions (W to kW) and varying treatment times (seconds to hours) using different plasma sources such as dielectric barrier discharge (DBD), arc, radio frequency (RF) and microwave (MW) for the surface functionalization. Most of the researchers have experienced both positive and negative co-relationships between principal parameters and surface functional groups (SFGs), surface area, porosity and other surface features such as roughness and hydrophilicity. However, a comprehensive review on the effects of these parameters on the final material properties is lacking. Therefore, this Review focuses on the recent developments in the utilization of plasma as a surface activation technique for activated carbon. Furthermore, an in-depth analysis of the relationship between experimental parameters and the resultant surface features of activated carbon is carried out and discussed. The functionalization mechanisms related to plasma activation have also been illustrated. The aging effect, which negatively impacts surface functionalized activated carbon, is also emphasized. Finally, the recent advances in applications of SFAC, challenges and future perspectives are discussed in detail.

Insights into the polysaccharides and proteins production from Penicillium citrinum during bioleaching of spent coin cells

The essential role of polysaccharides and proteins of extracellular polymeric substances (EPS) has been well known in the bioleaching process. However, there is no information on the role of these compositions in the bioleaching of spent coin cells (SCCs). This study investigated protein and polysaccharide production as biological macromolecules during the bioleaching of SCCs at various pulp densities using adapted Penicillium citrinum. The adaptation improved the tolerance index of fungi for the bioleaching up to a pulp density of 30 g/L. The EPS analysis indicated that loosely bound EPS (LB-EPS) contained a high concentration of polysaccharides. Instead, the most protein content was concentrated at tightly bound EPS (TB-EPS). Both protein and polysaccharide keep growing up to 20 g/L of pulp density during the entire period of bioleaching, and the maximum binding rate of Mn and Li to EPS was 43% and 15%, respectively. Pearson correlation indicated the positive correlation of the protein and the polysaccharides content on bioleaching efficiencies. From the FTIR spectroscopy, the principal functional groups on Mn and Li binding were OH and carboxyl. The FE-SEM analysis revealed the deformation of EPS at 30 g/L of pulp density, which suggested the toxic effect of this pulp density.

Equilibrium and kinetics of sorption and resorption of acid and basic dyes using the pulp of carob pods

Being an abundant product in Algeria, pulp of carob pods (PCP) was used in this study as a biosorbent for Methylene blue (MB) and Congo red (CR) removal from aqueous media in batch mode in two successive steps. Once the first dye is adsorbed, the biosorbent is used as is to adsorb the second dye in order to study the interactions between them. Characterization of PCP by FTIR spectroscopy, Scanning Electron Microscopy (SEM), EDX, and point of zero charge showed that the principal functional groups present at the surface are oxygenated with a pHpzc value of the 7.2. Contact time of 60 min was amply sufficient to reach equilibrium for both dyes onto PCP and recuperated biosorbents. pH effect on the biosorption onto PCP shows a behavioral divergence between both dyes. Maximum biosorption uptake of CR was observed at pH value of 6.38 while pH variation has no remarkable influence on MB biosorption and the initial pH solution of 5.75 was taken for subsequent biosorption experiments. The adsorption isotherms obtained are in good agreement with the models of Langmuir and Freundlich and the kinetics are well described by the pseudo-second-order model.

Novel Myco-Coagulant Produced by Lentinus squarrosulus for Removal of Water Turbidity: Fungal Identification and Flocculant Characterization.

Several river water fungal strains (RWF-1 to RWF-6) were isolated to investigate the potential of having coagulant properties from the metabolites produced by the fungus. The myco-coagulant produced from the liquid-state process was characterized and tested for flocculation of kaolin water. Molecular identification of the fungal strain isolated from river water and characterization of the myco-coagulant produced by the strain are presented in this paper. The genomic DNA of the fungal 18S ribosomal ribonucleic-acid (rRNA) and 28S rRNA genes were used and the species was identified as Lentinus squarrosulus strain 7-4-2 RWF-5. The characterization of myco-coagulant by Fourier-transform infrared spectroscopy (FTIR) showed that hydroxyl, carbonyl, amide and amine groups as principal functional groups were present in the new myco-coagulant. The mean zeta potential value of the myco-coagulant was −7.0 mV while the kaolin solution was −25.2 mV. Chemical analyses of the extracellular myco-coagulant revealed that it contained total sugar (5.17 g/L), total carbohydrate (237 mg/L), protein (295.4 mg/L), glucosamine (1.152 mg/L); and exhibited cellulase activity (20 units/L) and laccase activity (6.22 units/L). Elemental analyses of C, H, O, N and S showed that the weight fractions of each element in the myco-coagulant was 40.9, 6.0, 49.8, 1.7 and 1.4%, respectively. The myco-coagulant showed 97% flocculation activity at a dose of 1.8 mg/L, indicating good flocculation performance compared to that of polyaluminum chloride (PAC). The present work revealed that the fungal strain, L. squarrosulus 7-4-2 RWF-5 is able to produce cationic bio-coagulant. The flocculation mechanism of the novel myco-coagulant was a combination of polymer bridging and charge neutralization.

New insights into nitrogen removal potential in urban river by revealing the importance of microbial community succession on suspended particulate matter

The importance of suspended particulate matter (SPM) in nitrogen removal from aquatic environments has been acknowledged in recent years by recognizing the role of attached microbes. However, the succession of attached microbes on suspended particles and their role in nitrogen removal under specific surface microenvironment are still unknown. In this study, the causation among characteristics of SPM, composition and diversity of particle-attached microbial communities, and abundances of nitrogen-related genes in urban rivers was firstly quantitatively established by combing spectroscopy, 16 S rRNA amplicon sequencing, absolute gene quantification and supervised integrated machine learning. SPM in urban rivers, coated with organic layers, was mainly composed of silt and clay (87.59–96.87%) with D50 (medium particle size) of 8.636–30.130 μm. In terms of material composition of SPM, primary mineral was quartz and the four most abundant elements were O, Si, C, Al. The principal functional groups on SPM were hydroxyl and amide. Furthermore, samples with low, medium and high levels of ammoxidation potential were classified into three groups, among which significant differences of microbial communities were found. Samples were also separated into three groups with low, medium and high levels of denitrification potential and significant differences occurred among groups. The particle size, content of functional groups and concentration of SPM were identified as the most significant factors related with microbial communities, playing an important role in succession of particle-attached microbes. In addition, the path model revealed the significantly positive effect of organic matter and particle size on the microbial communities and potential nitrogen removal. The content of hydroxyl and temperature were identified as the most effective predicting factors for ammoxidation potential and denitrification potential respectively by Random Forests Regression models, which had good predictive performances for potential of ammoxidation (R2 = 0.71) and denitrification (R2 = 0.61). These results provide a basis for quickly assessing the ability of nitrogen removal in urban rivers.

Physicochemical properties and surface activity characterization of water-soluble polysaccharide isolated from Balangu seed (Lallemantia royleana) gum

The aim of this research was to investigate physicochemical properties and surface activity characterization of Balangu seed polysaccharide and its fractions. Balangu seed (Lallemantia royleana) gum was fractionated according to its fractions molecular weight difference by ethanol. Its fractions were named PER-Balangu (high molecular weight) and SUPER-Balangu (low molecular weight). The results showed the molecular weight value of Balangu, PER-Balangu and SUPER-Balangu were 3120 kDa, 6130 kDa and 2050 kDa, respectively. Moreover, the highest and lowest protein content related to SUPER-Balangu (10.8%) and PER-Balangu (6.03%), respectively. The uronic acid value of Balangu, PER-Balangu and SUPER-Balangu were 15.16%, 9.75% and 20.35%, respectively. The FT-IR spectra showed the principal functional groups included of (OH), (C–H), (−COO−) and (C–O–C). The intrinsic viscosity value of Balangu, PER-Balangu and SUPER-Balangu were 45.11 dL/g, 29.4 dL/g and 36.51 dL/g, respectively. SUPER-Balangu improved the surface activity properties, which was significantly reduced by increasing SUPER-Balangu concentration (p < 0.05). According to the result of this study, protein content and molecular weight play a pivotal role in the surface activity of Balangu and its fractions. Also, Balangu, PER-Balangu and SUPER-Balangu had structure features difference in finger-print area of FTIR spectrum.

The Application of Monkey Cola Pericarp (Cola lepidota) in the Removal of Toluene from Aqueous Medium

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied.&#x0D; The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.

Stability Series for the Complexation of Six Key Siderophore Functional Groups with Uranyl Using Density Functional Theory.

Determining stability constants of uranyl complexes with the principal functional groups in siderophores and identifying stability series is of great importance to predict which siderophore classes preferentially bind to UVI and, hence, impact uranium speciation in the environment. It also helps to develop resins for scavenging UVI from aqueous solutions. Here, we apply a recently developed computational approach to calculate log β values for a set of geochemically relevant uranium organometallic complexes using Density Functional Theory (DFT). We determined the stability series for catecholate, hydroxamate, α-hydroxycarboxylate, α-aminocarboxylate, hydroxy-phenyloxazolonate, and α-hydroxyimidazole with the uranyl cation. In this work, the stability constants (logβ110) of α-hydroxyimidazolate and hydroxy-phenyloxazolonate are calculated for the first time. Our approach employed the B3LYP density functional approximation, aug-cc-pVDZ basis set for ligand atoms, MDF60 ECP for UVI, and the IEFPCM solvation model. DFT calculated log β110 were corrected using a previously established fitting equation. We find that the siderophore functional groups stability decreases in the order: α-hydroxycarboxylate bound via the α-hydroxy and carboxylate groups (logβ110 = 17.08), α-hydroxyimidazolate (logβ110 = 16.55), catecholate (logβ110 = 16.43), hydroxamate (logβ110 = 9.00), hydroxy-phenyloxazolonate (logβ110 = 8.43), α-hydroxycarboxylate bound via the carboxylate group (logβ110 = 7.51) and α-aminocarboxylate (logβ110 = 4.73). We confirm that the stability for the binding mode of the functional groups decrease in the order: bidentate, monodentate via ligand O atoms, and monodentate via ligand N atoms. The stability series strongly suggests that α-hydroxyimidazolate is an important functional group that needs to be included when assessing uranyl mobility and removal from aqueous solutions.

Study of Sorption Equilibrium of Biopolymers Alginic Acid and Xanthan with C.I. Disperse Yellow 54

Disperse yellow 54 (DY54) was adsorbed onto two biopolymers, alginic acid and xanthan. The adsorption isotherms for the biopolymer-DY54 system showed that the adsorption mechanism can best be described by Zimm-Bragg theory. UV-Visible, FT-IR and MicroRaman studies suggest that DY54 is bounded to both biopolymers alginic acid and xanthan through hydrogen bonding. Keto group of dye and hydroxyl groups of sugar residues from two polysaccharides were the principal functional groups involved in sorption mechanism.

A review of past and present summer primary production processes in the Ross Sea in relation to changing ecosystems

We analyse primary production processes during austral summer 1996 and 2001 in different environmental conditions such as ice-free waters and extensive ice-covered areas. Spatio-temporal distribution of phytoplankton biomass and functional groups along with photosynthetic parameters are presented. Production vs irradiance (P vs E) experiments were performed using 14 C incubations at several stations and three or four different depths to define the eco-physiology of phytoplankton communities.The results of the oceanographic campaign conducted in ice-free waters of the Ross Sea (summer 1996) emphasize that these ecosystems are characterized by high nutrient low chlorophyll (HNLC) conditions due to limiting factors (eg Fe). Conversely, the results of the oceanographic cruise in extensively packice-covered areas (summer 2001) indicate that the average phytoplankton biomass (estimated from Chl a ) was about three times the values recorded in ice-free conditions, but the primary production was relatively lower. In fact, in situ primary production and P vs E experiments over few days show that high primary production values occurred in most of the area, but only within the first five meters of the water column and the melting pack ice. Notwithstanding some high values of phytoplankton biomass during the 2001 campaign, water column stability, similar irradiance levels along the water column, photosynthetic capacity was suppressed in deeper layers, indicating a low carrying capacity of the pelagic ecosystem due to iron limitation, as shown by low values of the photo-chemical efficiency of photosystem II (PSII), variable fluorescence and maximal fluorescence ratio (Fv/Fm). In contrast with a very high variability in phytoplankton biomass at several temporal and spatial scales, photosynthetic parameters (P B max , a, E k ) varied within narrow ranges. Relevant changes in phytoplankton abundance and species composition are reported in this study although the environmental factors that drive these changes in primary production processes and prevalence of principal functional groups of phytoplankton communities compared to the past (1996 and 2001) are still unknown. The effect of these changes on the carrying capacity of Ross Sea ecosystems, carbon export and the potentially new asset of the food web will need to be determined.

Negative effects of an invasive grass, but not of native grasses, on plant species richness along a cover gradient

AbstractImpacts of invasive plants on plant communities are not universal, and effects may differ depending on the life form of the invading species. At three sites in the Brazilian Pampa region, we assessed the effects of invasion by Eragrostis plana Nees, considered to be the most problematic invasive plant in South Brazilian grasslands, on local plant communities. Specifically, we evaluated effects on species richness, community evenness and richness of principal functional groups along an invasion gradient. Based on plant community data, we also evaluated the effects of dominant native species on the same plant community features, thus being able to assess the relative impacts of an invasive species compared to abundant native species. Eragrostis plana invasion reduced total plant richness, with some distinct effects regarding plant functional groups, and differently from other coexisting native species that did not show the same effects even when of high abundance. Grasses were the most affected plant group when E. plana cover increased, consistent with the limiting similarity hypothesis. Overall, our results indicate clear negative effects of this invasive plant on the grassland communities. Comparing the effects of an invasive species to those of coexisting natives is crucial for disentangling the real impact of an invader. Our results demonstrate that effects are consequence of species identity, and not only of high abundances.

Resistance against AC corona discharge of micro-ATH/ nano-Al2O3 co-filled silicone rubber composites

Exposure to corona discharge damages the polymeric structure of alumina trihydrate (ATH) filled silicone rubber composite insulators. In this work, an attempt has been made to enhance the resistance against sustained long term corona exposure of ATH filled silicone rubber by fabricating its co-filled composites through addition of a small amount of nano Al2O3. Fabricated specimens comprise a pristine sample of silicone rubber (SR), one micro {40wt% ATH (MSR)} composite and two co-filled {39wt% ATH+1wt% nano Al2O3 (MSR1%) and 38wt% ATH+2wt% nano Al2O3 (MSR2%)} composites with total particle loading of 40wt%. They are subjected to AC corona exposure produced from a needle electrode tip for seven days. Performance evaluation is achieved through SEM (Scanning electron microscopy), FTIR (Fourier transform infrared spectroscopy), hydrophobicity, and surface roughness. Test results show severe material ruptures occurred in SR but damage in the form of pits and voids in MSR and MSR1% in the area directly below the needle tip. Interestingly, MSR2% exhibits subdued damage and a compact lump structure. The hydrophobicity recovery rate is significantly higher below the needle tip than in the vicinity, and in the SR as compared to the other composites. Also noted is higher increment in average and peak surface roughness below needle tip, and strong resistance to roughness increment by MSR2%. FTIR results show higher concentration of hydroxylation and aluminum nitrites in MSR and the absorbance intensities of principal functional groups show fewer deviations in MSR1% and MSR2% relative to their virgin states. Based on experimental results, it is concluded that corona resistance of micro ATH filled silicone rubber can be enhanced through addition of small amount of Al2O3 by fabrication of co-filled composites.

Extraction and partial characterisation of antioxidant pigment produced by Chryseobacterium sp. kr6

Pigments synthesised by Chryseobacterium sp. kr6 growing on feather waste were extracted and characterised. The pigment extract was characterised by KOH test, UV–vis, CIELAB colour system, HPLC-DAD-MS, FTIR and its antioxidant capacity was evaluated. A positive bathochromic shift was observed when kr6 colonies or pigment extracts were subjected to alkaline solution (20% KOH) and a λmax at 450 nm was detected for acetone extracts, although no typical fine structure of carotenoids was detected in the electomagnetic spectra. The HPLC profile of the extracted pigment showed that the compound has three different peaks with λmax near 450 nm. The FTIR analysis shows some principal functional groups from a flexirubin-like molecule. The pigmented compound also presents antioxidant activity evaluated by the scavenging of the ABTS radical.

Characteristics of Compost Obtained from Winemaking Byproducts

A model procedure for the sustainable management of plant biomass related to wine production, namely vine branches from agricultural practices in the vineyard and marcs remaining after grapes crushing, was devised. An artificial humification process was set up that could respond to the needs of environmental sustainability and could be a safe way to be reintroduce in the vineyard part of the organic matter previously exported, thus contributing to recover or maintain vineyard soil fertility. Two different strategies for composting were tested, namely a static pile, made by branches and marcs, and a pile that was fed twice a year alternatively with vine branches and grape marcs. The experimentation lasted 710 days, during which environmental parameters, i.e. temperature and rainfalls were monitored. Growth dynamics of the principal functional groups of microorganism were followed. A characterization of the composted material was obtained by measuring several parameters among which, pH, carbon, nitrogen, sulfur and heavy metals content. The characteristics of the produced compost fulfill the requirements prescribed by the Italian legislation regarding the use of compost as soil amendment. Germination tests demonstrated the absence of phytotoxicity and conversely evidenced a stimulating activity towards root development.

Evaluation of thermal stability and time resolved acoustic fingerprint spectra of 1-(2-methoxy,-3,5-dinitrophenyl)-1H-1,2,3-triazole

The paper reports the study of thermal stability and decomposition mechanisms of the newly synthesized phenyl series energetic molecule named 1-(2-methoxy,-3,5-dinitrophenyl)-1H-1,2,3-triazole (S5) using time resolved pulsed photoacoustic (PA) pyro analysis technique. The thermal PA spectra of the compound was recorded using a Q-Switched Nd-YAG laser (532nm, 7ns, 10Hz). TG-DTA technique was carried out for ascertaining the melting and decomposition temperature of the compound. The results of these two methods confirm that S5 is thermally stable in the range of 30–350°C. We have earlier reported that phenyl series 1,2,3-triazoles require high incident laser energy than that of benzyl series 1,2,3-triazoles [1]. However, our further investigation shows that the change in the position of principal functional groups affects the process of thermal decomposition. Also, the thermal stability of the compound is evaluated on the basis of quality factor (Q) of the PA cavity. Further, we have used GC–MS and FTIR techniques to identify some of the gaseous components released from the compounds.

Chromium(VI) removal from aqueous medium by maize cane and agave bagasse biomasses

ABSTRACTChromium(VI) is a major water pollutant from industrial effluents whose concentration is to be reduced within the permissible limits. In this paper, the use of maize cane and agave bagasse as inexpensive adsorbent for the removal of Cr(VI) from aqueous solutions is considered. In the first place, they were conditioned and characterized to determine their physicochemical properties with scanning electron microscopy; the elemental composition with energy-dispersive x-ray spectroscopy (EDS); the principal functional groups with Fourier transform infrared spectroscopy; thermal stability with thermogravimetric analysis; and surface properties by specific surface hydration kinetics, point of zero charge determination by mass titration, and active site density are described. In the second place, their adsorption properties for Cr(VI) from aqueous solution were evaluated in a batch system. The kinetics of Cr(VI) sorption with both natural adsorbents were described with a pseudo-second-order model. Equilibrium data were found to be best represented for both adsorbents by the Freundlich isotherm model. Maize cane and agave bagasse can be effectively used as an adsorbents for the removal of Cr(VI) ions from the aqueous solution.