Carbon Hydrogen Nitrogen Research Articles

Organo acid-activated clays for water treatment as removal agent of Eosin-Y: Properties, regeneration, and single batch design absorber

Organoclays have been proposed as efficient removal agents for colored wastewater treatment. In this study, organo-acid-activated clays were investigated for their ability to remove eosin Y dye molecules. Firstly, the clay was acid activated using sulfuric solution at 90 °C for overnight. Secondly, the resulting materials were treated by hexadecyltetramethylammonium bromide solutions to obtain organo-acid-activated clays. Several techniques were used, such as X-ray diffraction, carbon hydrogen nitrogen analysis, silicon-29 and carbon-13 solid-state nuclear magnetic resonance, and nitrogen adsorption isotherms. The cation exchange capacity values were reduced and the specific surface area values increased from 80.1 m2/g to 183.2 m2/g during the acid activation process. The resulting organo-acid-activated clays had a similar expansion of interlayer spacing of 3.90 nm with less intercalated hexadecyltetramethylammonium surfactants, ranging from 0.80 mmol/g to 1.22 mmol/g; 13C solid NMR indicated that the intercalated surfactants exhibited different degree of conformation. Many factors, including the solid dose, solution pH, amount of intercalated surfactants, and starting eosin-Y concentrations, were studied in relation to the removal capabilities of organo acid-activated clays. Based on the Langmuir model, the removal capacity of the organo acid-activated clays ranged from a minimum of 43.5 mg/g to a maximum of 79.3 mg/g, dependent on the surfactant quantities and acid activation degree. , and the pH. The removal percentage of eosin-Y was increased from 50.5 % to 80.8 % by treating the organo acid-activated clay with HCl solution before the removal procedure. Regeneration and reuse of two selected organo acid-activated clays were carried out for seven successive cycles, and a reduction in the initial efficiency was in the range of 26.4 %–30.1 %. However, for organoclay (without acid activation), approximately 52.1 % efficiency was maintained. Using the Langmuir model and mass balance equations, a single-stage adsorber design was suggested for different dye volumes at a constant starting concentration.

Rice Straw‐Derived Biochar as Anode Material for Lithium‐Ion Battery: A Step toward Sustainable Development

In the present study, sustainable upscaling of rice straw, an agri‐residue, is explored as the way to obtain active material to prepare anode for use in lithium‐ion batteries (LIBs). The biochar having high carbon and low silica content is prepared by initial chemical treatment of rice straw followed by its pyrolysis. The pristine and modified biochar are characterized using Brunauer‐Emmett‐Teller surface area, energy dispersive X‐ray spectroscopy, carbon hydrogen nitrogen sulphur elemental analysis, scanning electron microscopy, X‐Ray power diffraction, Fourier transform infrared spectroscopy and Raman analysis and the modified biochar show an enhancement in graphitic carbon content. A coin cell is assembled using anode prepared from modified biochar. The coin cell is subjected to electrochemical testing and had a discharge capacity of 352 mA.h g−1. Further, the coin cell is tested for 100 cycles and a columbic efficiency of 99.7% was obtained. Therefore, biochar derived from pyrolysis of rice straw has the potential to be used as anode material for LIBs.

Sustainable bio-oil from banana peel waste biomass: Optimization study and effect of thermal drying

<p>Banana waste has a high level of volatile matter, making it a promising feedstock for pyrolysis in bio-oil generation. Thus, an oven drying method optimization study was conducted to find the drying process of Saba banana peel on flap opening and fan speed. Based on the ANOVA results, it was found that the drying process using 60% fan speed and 40% flap opening for 6 hours of drying time could remove 84.07% of the moisture content from the banana peel. Differential thermal analysis (DTA) was employed to characterize dried banana peels. The TGA study showed that the volatile matter concentration of the dried banana peels was 76.47% when using the ASTM drying method and 70.95% when using the improvement parameter optimization for the drying process. The bio-oil's high heating value (HHV) at 300 °C was 38.88 MJ/kg. The yields of bio-oil, biochar, and syngas obtained from the pyrolysis process were 16.6%, 36.45%, and 46.96%, respectively. The carbon hydrogen nitrogen sulfur (CHNS) ultimate analysis study showed a bio-oil elemental composition of 65.59% carbon, 8.27% hydrogen, 2.94% nitrogen, 0.93% sulfur, and 22.27% oxygen. Fourier transform infrared (FTIR) spectroscopy showed that functional groups including alcohol, alkane, phenol, and primary alcohol are present.</p>

Evaluation of antibacterial activity of an experimental dental adhesive containing synthesized quaternary ammonium compound: in vitro study

BackgroundDental adhesives with immobilized antibacterial agents are formulated to combat bacterial invasion along the tooth-restoration interface. This study aims to evaluate the antibacterial effect of synthesized quaternary ammonium compound (QAC) incorporated into commercial dental adhesive.MethodsQAC was synthesized from 2-(Dimethylamino) ethyl methacrylate and 1-Bromobutane and characterized using CHN (Carbon, Hydrogen, Nitrogen), FTIR (Fourier transform infrared) and H+NMR (Proton nuclear magnetic resonance) analyses. The synthesized QAC was assessed for its cytotoxicity and its antibacterial activity against S. mutans using disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), time-kill kinetics test, and TEM imaging. The QAC was added to the primer of a commercially available adhesive (OptiBond XTR) at two concentrations; 20 and 40 mg mL−1 representing the MIC and MBC, respectively. The antibacterial properties of the experimental adhesives, commercial antibacterial adhesive Clearfil SE Protect containing 12-methacryloyloxydodecylpyridinium bromide (MDPB), and commercial vehicle (OptiBond XTR) were compared using time-kill kinetics test. Statistical analysis by ANOVA followed by tukey post-hoc test (P < 0.05).ResultsDisc diffusion and time-kill kinetics tests showed potent antibacterial action of QAC, both in the unpolymerized and the cured forms. MIC and MBC were 20 and 40 mg mL−1 respectively. There was no statistically significant difference between experimental adhesives and Clearfil Protect with more than 99% reduction in bacterial count, while OptiBond XTR showed no bacterial killing up for up to 10 h.ConclusionsThe synthesized QAC added to a commercially available adhesive imparted antibacterial properties, thus providing an affordable adhesive system to the local market.

Characterization of Municipal Solid Waste Generated in Some Egyptian Cities

Municipal solid waste (MSW) poses a cumulative problem related to many aspects, namely, social, economic, and cultural. Therefore, such a situation must be accompanied by the development of well-established management systems starting with the knowledge of MSW quantities, its quality and characterization and ending with a suitable landfilling technique. This work aims to characterize Egyptian municipal solid waste generated from two cities in Great Cairo, where 45 samples were collected regularly. The research was carried out by researchers in the Chemical Engineering Department at Cairo University and selected undergraduate students from October to December 2020. The collected MSW was characterized by evaluating the quality and quantity of generated waste. Selected properties considered were: composition (including the organic fraction, papers, plastics, textiles, metals, glass, and others), density, moisture content, calorific value, and Carbon Hydrogen Nitrogen Sulfer (CHNS) chemical elemental analysis. The results obtained showed that the organic fraction was dominant to other fractions (4287%) and the carbon content was more than 47% and the calorific values to range between 4360-12277 kJ/kg. The results obtained were used as a base for a waste management proposal, either from mass recovery for highrecyclable samples or energy recovery for high calorific value waste. In other circumstances, waste-to-energy WTE processes were recommended as a promising solution to developing countries in the world where the energy demand is essential for the life.

Physiological, biochemical and structural changes in tomato plants by vermicompost application in different exposure periods under glass house conditions

In modern era, various inorganic fertilizers and pesticides are used as plant growth supplements in a variety of crop in order to gain maximum output and also reported as hazardous to mankind as well as environment. In addition, some of the plants died in initial phase of the growth after germination due to poor nutrient content of the soil or exposure to biotic stresses. In the beginning of sustainable agriculture, these chemical fertilizers were replaced with some alternative growth boosters such as organic fertilizers. In the present study, vermicompost was prepared using garden waste and cattle dung followed by analysis of various physico-chemical properties. Then tomato seeds were allowed to germinate in soil and supplemented with different doses of vermicompost (0–100%). The plants were harvested after 10 and 45 days of their germination and tissues were subjected to analysis of various morphological and biochemical parameters. Morphological parameters included root length, shoot length, root fresh weight, shoot fresh weight and number of leaves. Whereas biochemical parameters such as protein content, antioxidative enzymes (catalase, superoxide dismutase, ascorbate peroxidase, polyphenol oxidase), non-enzymatic antioxidants (ascorbic acid, glutathione, tocopherol), osmolytes (proline, carbohydrate), photosynthetic pigments (chlorophyll, carotenoid) and secondary metabolites (phenol, flavonoid, anthocyanin) were estimated on UV–visible spectrophotometer using standard protocols. Further, structural analysis of plant tissue was done using fourier transform infrared spectroscopy spectra (FTIR) and carbon hydrogen nitrogen (CHN) elemental analyzer. Results obtained from the present study revealed significant difference in all morphological and biochemical markers at both 10 and 45 days intervals of time. Further, growth of all plants was found to be directly proportional to the concentration of vermicompost and exposure duration. FTIR spectra and CHN analyses reveal the breakdown of various complex compounds and their transformation from Vcom amended soil to roots of plants. This is the first study in which significant changes were observed in growth, physiology and structural composition of tomato plants at two different exposure periods (10 and 45 days) under glass house conditions which further concluded that vermicompost has a significant potential for increasing plant growth.

Differential Cytotoxic Activity of a New Cationic Pd(II) Coordination Compound with N4-Tetradentate Hybrid Ligand in Cancer Cell Lines

Objective: Successful cancer treatment still requires the discovery of novel compounds that hold promise for chemotherapeutics. The objective of this study was to examine the effectiveness of a newly synthesized cationic palladium(II) coordination compound that functions via several pathways to provide an efficient therapeutic option for various cancer cells. Materials and Methods: A new cationic palladium(II) coordination compound, [Pd(L)]Cl2·H2O, denoted as Complex 1, where the ligand L is the compound 6,6'-bis(NH-benzimidazol-2-yl)-2,2'-bipyridine), was synthesized and characterized by the attenuated total reflectance (ATR) - fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1 H NMR), electrospray ionization mass spectrometry (ESI-MS), and carbon-hydrogen-nitrogen (CHN) analyses. The density functional theory (DFT) calculations show the coordination sphere around the metal center in Complex 1 to be made up of tertiary N atoms of the pyridine (py) and benzimidazole (bim) rings completing the square-planar geometry with significant distortion. The anti-growth/cytotoxic activity of the complex was determined using the sulforhodamine B (SRB) and adenosine triphosphate (ATP) viability assays for 24 and 48 h in vitro. The study evaluates the determinations for annexin V-propidium iodide (PI) positivity, mitochondrial membrane potential loss, Bcl-2 protein inactivation, and deoxyribonucleic acid (DNA) damage to investigate the cell death mode and its partial mechanism. Results: Complex 1 caused cytotoxicity in a dose-dependent manner in all the cell lines used, with IC50 values ranging from 2.6-8.8 μM for 48 h. Among the cancer models, colon and breast cancer cell lines underwent cell death by well-described apoptosis through the intrinsic pathway involving the mitochondria. However, the other cell lines did not show such a cell death modality. This implies that differential cell death modes operate based on the cancer type. Conclusion: For the treatment of breast and colon cancers, the complex 1 appears to be a unique, promising complex. Therefore, complex 1 deserves further attention for proof of concept in animal models.

Effect of Vanadium on the Microstructure, Transformation Temperatures, and Corrosion Behavior of NiTi Shape Memory Alloys

Abstract Ni50Ti50-xVx (x = 0, 1, 2, 3 at%) shape memory alloys were prepared by vacuum induction melting. They were homogenized and then hot rolled. Carbon hydrogen nitrogen oxygen sulfur (CHNOS) and X-ray diffraction (XRD) analyses were carried out on the alloys to find out the oxygen and carbon contents and the phases present in the alloys. Transformation temperatures determined by differential scanning calorimetry indicate that the addition of vanadium reduces the transformation temperatures. Corrosion studies were carried out in Hanks’ solution, while potentiodynamic polarization tests were done to calculate the rate of corrosion of the alloys. Two significant parameters were analyzed from the Tafel graph, namely, corrosion rate and corrosion potential. A comparison of these properties of the alloys was also made with commercially pure titanium and binary NiTi alloys. Among the NiTiV alloys, Ni50Ti47V3 (at%) alloy was found to undergo the least rate of corrosion. With the increasing vanadium content, the rate of corrosion was found to decrease. Scanning electron microscopy (SEM) analysis of the corroded surface shows that pitting was the main mechanism of corrosion in these alloys. Results show that the addition of V to NiTi has a positive effect on the corrosion properties of the alloys. Elaborate results are discussed in detail in this article.

Synthesis and evaluation of novel xanthene-based thiazoles as potential antidiabetic agents.

A series of xanthene-based thiazoles was synthesized and characterized by different scpectroscopic methods, i.e. Proton nuclear magnetic resonance (1 H NMR), carbon nuclear magnetic resonance (13 C NMR), infrared spectroscopy, carbon hydrogen nitrogenanalysis, and X-ray crystallography. The inhibition potencies of 18 newly synthesized thiazole derivatives were investigated on the activities of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase (α-Amy), and α-glycosidase (α-Gly) enzymes in accordance with their antidiabetic and anticholinesterase ability. The synthesized compounds have the highest inhibition potential against the enzymes at low nanomolar concentrations. Among the 18 newly synthesized molecules, 3b and 3p were superior to the known commercial inhibitors of the enzymes and have a much more effective inhibitory potential, with IC50 : 2.37 and 1.07 nM for AChE, 0.98 and 0.59 nM for BChE, 56.47 and 61.34 nM for α-Gly, and 152.48 and 124.84 nM for α-Amy, respectively. Finally, the optimized 18 compounds were subjected to molecular docking to describe the interaction between thiazole derivatives and AChE, BChE, α-Amy, and α-Gly enzymes in which important interactions were monitored with amino acid residues of each target enzyme.

Synthesis and Biological Activity of New Derivatives of Thiazolidine and Oxazepine-Linked to Pyridine Moieties

This research includes reaction and condensation between substituted 4-aminopyridine and 4-(N, N-dimethyl amino benzaldehyde) to produce Schiff base derivative (3), the compound (3) was selected to react with a different compound such as Thioglycolic acid, Phthalic anhydride, and maleic anhydride, to produced new ring of Thiazolidine derivatives and oxazepine derivatives structures (4,5,6,7,8,9,10,11,12), respectively. The final compound was characterized the structure by Fourier transform-infrared spectroscopy, H-Nuclear magnetic resonance (H-NMR) in addition to the Carbon, Hydrogen, Nitrogen (CHN) analyzer. Biological activity has been considered for the final structures and achievements of multi drugs.

A novel microbial-assisted method for sodium bicarbonate production – Cleaner production, safe and facile synthesis

The human tendency to new, cleaner, and safer methods for the production of materials has led to extensive eco-friendly studies. Herein, urea ((NH2)2CO) was exposed to bio-catalyzed urease enzyme from Sporosarcina pasteurii (formerly known as Bacillus pasturii). After hydrolysis of urea, the gassing of CO2 led to the production of sodium bicarbonate (NaHCO3). The final product was validated for its crystallographic, microstructural, and elemental properties through X-ray diffraction (XRD), carbon-hydrogen-nitrogen (CHN) elemental analysis, field-emission scanning electron microscopy (FE-SEM), X-ray fluorescence (XRF) spectroscopy, and energy-dispersive X-ray (EDX) spectroscopy. These results, along with the chemical evaluation of chloride ion, proved that NaHCO3 was the major compound with a purity of > 76 %. This finding confirmed that cleaner and facile production of NaHCO3 is possible by our defined novel enzymatically-modified Solvay method. Besides removing hazardous materials before and after the process (raw materials and residues), this method simultaneously highlights the potential for converting CO2 captured from the environment or gases released from different industries to NaHCO3 a highly applicable material for pharmaceuticals, food, and other industries.

Cationic inulin as a new surface decoration hydrocolloid for improving the stability of liposomal nanocarriers

The aim of the present study was to investigate the cationization of inulin with Williamson’s etherification method, and compare cationic inulin with unmodified inulin coatings for stabilizing nanoliposomes (NLPs). The synthetized cationic inulin was characterized by Fourier transforms infrared (FT-IR) spectroscopy, carbon hydrogen nitrogen (CHN) elemental analysis, and energy-dispersive X-ray spectroscopy. Three concentrations of inulin and cationic inulin (1, 2, and 4 mg/mL) were used for the coating of NLPs. The concentration of 4 mg/mL was found to be optimal for inulin and cationic inulin as surface coating, on the basis of particle size, zeta potential, and microstructural morphology. The lowest values of particle size (93.41 nm), polydispersity index (0.25), and negative zeta potential (−24.41 mV) were related to the coated NLPs with cationic inulin at a concentration of 4 mg/mL. The transmission electron microscopy image of the coated NLPs with cationic inulin exhibited a spherical and core-shell structure. The coated NLPs with cationic inulin showed the highest thermal stability, physical stability, and oxidative stability. In conclusion, cationic inulin coating conferred a stronger protection than the unmodified inulin coating of NLPs. The technique developed here can be applied for surface decoration of NLPs to improve their stability.

Pharmacophore Based Design, Synthesis and Theoretical Conformational Analysis of Some Extended Aryl Hydrazones as Potential Anticonvulsant

A series of hydrazones were synthesized by condensing substituted hydrazides with appropriate carbonyl compounds. The chemical structures of the synthesized compounds were confirmed by infrared, proton nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, mass ((4-chloro-phenylamino)-acetic acid [1-(4-chlorophenyl)-phenyl-methylene]-hydrazide and (2,4-dichloro-phenylamino)-acetic acid (3-oxo- 1,3-dihydro-indole-2-ylidene)-hydrazide only) spectral data and carbon hydrogen nitrogen analysis. The title compounds were screened for their anticonvulsant activity against mice at doses of 30 mg/kg, 100 mg/kg and 300 mg/kg. The preliminary anticonvulsant screening data of this series resulted in the identification of two lead compounds (2,4-dichloro-phenylamino)-acetic acid (3-oxo-1,3-dihydro-indole- 2-ylidene)-hydrazide and (2,4-dichloro-phenylamino)-acetic acid [1-(4-chlorophenyl)-phenyl-methylene]- hydrazide with excellent preliminary anticonvulsant profile with no neurotoxicity in maximal electroshock seizure and subcutaneous metrazol mice model.

Effect of carbonization on the surface and influence on heavy metal removal by water hyacinth stem-based carbon

PurposeThe aim of this study is to examine the effect of carbonization on the surface and its influence on heavy metal removal by water hyacinth based carbon.Design/methodology/approachDried water hyacinth stem was used as precursor to prepare carbon based adsorbent by pyrolysis method. The adsorbent proximate (ash, volatile matter and fixed carbon) and elemental (carbon hydrogen nitrogen sulfur) composition, surface area, pore size distribution, surface chemistry was examined and compared.FindingsThe results demonstrated that through carbonization in comparison to dried water hyacinth stem, it increased the surface area (from 58.46 to 328.9 m2/g), pore volume (from 0.01 to 0.07 cc/g), pore size (from 1.44 to 7.557 Å) thus enhancing heavy metal adsorption. The metal adsorption capacity of Cd, Pb and Zn was measured and analyzed through induced coupled plasma-mass spectrometer. At metal concentration of 0.1 mg/l adsorption rate for Cd, Pb and Zn was 99% due to increased large surface area, coupled with large pore size and volume. Furthermore, the adsorbent surface hydroxyl group (OH−) enhanced adsorption of positively charged metal ions through electrostatic forces.Practical implicationsIt is presumed that not only adsorption with synthetic wastewater but real wastewater samples should be examined to ascertain the viability of adsorbent for commercial application.Originality/valueThere are little or scanty data on the effects of carbonization on water hyacinth stem based carbon and subsequent effects on heavy metal removal in effluents.

Evaluation of lignin waste as potential carriers for phosphate solubilizing bio-fertilizers: A zero waste technology

Purpose Incineration of plant biomass and refusing lignin rich effluent from paper industry to water bodies were seen as usual practice. This product-oriented research had a promising solution for recycling agro waste. Likewise, high quality handmade papers from dead-dry leaves of Ficus citrifolia, Swietenia mahagoni, Pinus roxburgii and Musa acuminate were obtained. Lignin was found to improve soil fertility and nutrient reservoir for microbial growth. So, this research managed and utilized lignin as liquid carriers to phosphate solubilizing bio-fertilizers (PSBs)- Meyerozyma gullerimondi and Providencia rettgeri. Method Handmade papers made were checked for quality by determining breaking length, burst factor, and gram per square meter (GSM). The essential nutrients in lignin waste were analyzed using FESEM-EDX (Field emission scanning electron microscope- energy dispersive X-ray spectroscopy). This confirmed suitability of lignin as fermenting carrier media for phosphate solubilizing biofertilizer (PSBs). After fermentation, nutrients were quantified using Carbon Hydrogen Nitrogen Sulphur (CHNS analyzer), Inductively Coupled Plasma- Atomic Emission Spectroscopy and Atomic Absorption Spectroscopy. The nutritional uptake studies of lignin PSBs were done on Vigna unguiculata (L) Walp. Results Musa acuminate produced handmade papers with the highest breaking length and burst factor (1160 m, 10.43 kg/cm2) followed by Ficus citrifolia (960 m, 7.2 kg/cm2), Swietenia mahagoni (480 m, 13.75 kg/cm2) and Pinus roxburgii (546 m, 4.0 kg/cm2) leaves. This lignin PSBs increased the growth of Vigna unguiculata (L) plant. Conclusion High quality handmade papers were made from waste leaves. The lignin spent from pulping industry could be utilized as carriers to phosphate solubilizers.

Electronic, NLO, computational and interaction analyses of DAPVMPTFB crystals for electro-optics and electronic industrial utilities

2-{2-(4-Diethylamino-phenyl)-vinyl}-1-methyl-pyridinium-tetrafluoroborate(DAPVMPTFB) organic non linear optical (NLO) crystals are grown by slow evaporation method and analyzed for XRD, carbon hydrogen nitrogen sulphur and oxygen (CHNSO) analyzer, computational, influx and dielectric studies. X-ray diffraction (XRD) analysis demonstrated the lattice parameters (a-7.8969 Å, b-20.4867 Å, c-11.1989 Å, α = γ as 90° and β as 92.407°). The chemical formula of the as-synthesized crystal is C18H23BF4N2. The presences of elements are identified theoretically and experimentally. The surface roughness of as-prepared crystal was studied by atomic force microscopy (AFM) image analysis. The NLO is 1.15 times higher than the referenced KDP specimen due to strong H atoms of 23 in the specimen. The macro influx for filters is 4.7371 µm; the structural parameters, as well as energy, interactions and Halosian with dotted effect, molecular potential, interactions, internal in addition to the external fields, shape indexing; curvedness; fragmented patching; finger print region by computational based Hirshfeld analysis (HFA), are well portrayed using the software. The dielectric utility is mainly for industries in manufacturing semiconductors. The Oak Ridge Thermal Ellipsoid Plot (ORTEP) diagram portrays the grown crystalline structural portrayal as well as the supercell effect for special volume unit cells by software.

Synthesis of Chalcones as Potential α‐Glucosidase Inhibitors, In‐Vitro and In‐Silico Studies

Abstractα‐glucosidase inhibitors are potential antihyperglycemic agents. Seventeen chalcones derivatives (1–17) were synthesized by reactions of diversely substituted aldehydes with various ketones. The structures of compounds were characterized by using nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS) and carbon, hydrogen, nitrogen (CHN) analysis. These synthetic molecules were tested for α‐glucosidase inhibitory activity. Acarbose was used as a standard drug and positive control in this study which exhibited an IC50 of 2.91±0.02 μM. Of seventeen, nine molecules 1‐3, 5, 6, 8, and 11‐13 displayed significant inhibition with IC50 values 1.19±0.19 to 15.79±0.99 μM. Compound 6 {(E)‐3‐(3,5‐dichloro‐2‐hydroxyphenyl)‐1‐(p‐tolyl)prop‐2‐en‐1‐one} with hydroxy and chloro substitutions was found to be the most active compound and a novel compound of this library with IC50=1.19±0.19 μM. Active molecules were subjected to in silico study to determine binding interactions with target site of α‐glucosidase.

The impact of atmospheric pollution on outdoor cultural heritage: an analytic methodology for the characterization of the carbonaceous fraction in black crusts present on stone surfaces

COVID-19 has reduced tourism in both museums and historical sites with negative economic effect. The wellbeing and good preservation of monuments is a key factor to encourage again tourism. Historical monuments exposed to outdoor pollution are subjected to well known degradation phenomenon including the formation on their surface of black crusts (BCs) causing blackening and deterioration of the monuments and, as a consequence, a worst fruition by the visitors. The aim of this research is the development and validation of a novel method to characterize and quantify the various components present in the black crusts. SO2 together with the carbonaceous fraction (i.e. OC, organic carbon, and EC, elemental carbon) represent the main atmospheric pollutants involved in the process of BCs formation which consists in the partial transformation of the carbonate substrate into gypsum where black particles are embedded.A new methodology based on the use of TGA/DSC (Thermogravimetric Analysis/Differential scanning calorimetry) and CHN (Carbon, Hydrogen, Nitrogen) analysis was set up allowing to determine organic carbon and elemental carbon together with other components such as gypsum. Four standard mixtures simulating BCs composition were prepared and analysed by the set-up methodology. The new procedure was subsequently applied to study real BCs samples taken from monuments and historical buildings placed in cities heavily affected by atmospheric pollution and by PCA (principal component analysis) their main features, from the point of view of carbonaceous fraction, were highlighted.

Optimization and characterization of crude oil contaminated soil bioremediation using bacteria isolates:Plant growth effect

This study investigated the effect of soil pH, nitrogen-phosphorus ratio, crude oil concentration and bacteria isolates (from petroleum hydrocarbon-contaminated soil) concentration on the optimization of crude oil-contaminated soil bioremediation using central composite design. The responses were total petroleum hydrocarbons (TPH) and plant growth. A 60-day pot experiment was conducted. Natural soil, crude oil-contaminated soil and bioremediated soil were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), carbon-hydrogen-nitrogen (CHN) analyser and gas chromatograph-mass spectroscopy (GC–MS). Optimum predicted values were 4.69, 7.68 g/g, 250.05 mL/L and 568.35 cell/g for soil pH, nitrogen-phosphorus ratio, crude oil concentration and bacteria isolates concentration respectively. Experimental run at optimum point affirmed the accuracy of the developed models. Characterization revealed contamination of natural soil by hydrocarbons and their biodegradation via the action of active functional groups present in bacteria isolates. Conclusively, the bacteria isolates could be applied as effective scavenger for hydrocarbon biodegradation in crude oil contaminated soil.

Regeneration and carboxymethylation of cellulose and its derivatives: application assessment for brewery wastewater treatment

Coagulation–flocculation technique is usually employed in wastewater treatment by applying conventional inorganic materials such as alum and ferric chloride. Due cost to environmental challenges associated with the use of inorganic flocculants, biopolymers are gaining ground as alternative water treatment materials. In the present study, native cellulose and hemicelluloses isolated from sugarcane bagasse were used in the removal of turbidity and biological oxygen demand from industrial wastewater. Isolated native cellulose was modified to form regenerated cellulose (RC). Also, native cellulose, hemicellulose and RC were carboxymethylated using Na-chloroacetate. Thereafter, the functional groups on the carboxymethylated biopolymers were examined using Fourier transform infrared spectroscopy and the carbon–hydrogen–nitrogen–sulfur–oxygen elemental analysis. The degree of substitution (DS) for regenerated and carboxymethylated cellulosic materials was measured using recommended standard methods. Carboxymethyl cellulose (CMC) with 1.3 DS reduced turbidity and biological oxygen demand by 62.2 and 64%, respectively. Carboxymethyl regenerated cellulose (CMC-II) at 1.1 DS reduced turbidity and by 55.6 and 60%, respectively. Carboxymethyl hemicellulose (CMH) with 1.4 DS was capable of reducing turbidity and biological oxygen demand by 45.7 and 47%, respectively. Carboxymethyl cellulose and hemicellulose have rarely been used in the treatment of brewery wastewater. In the present study, these two novel materials showed a good prospect in removing biological oxygen demand and turbidity.