Calibration of CO and CO2 Monitors Used in Periodic Inspection of Vehicles at Fixed Stations for Environmental Control

Global efforts for environmental cleanliness through the control of gaseous emissions from vehicles are gaining momentum and attracting increasing attention. Calibration plays a crucial role in these efforts by ensuring the quantitative assessment of emissions for informed decisions on environmental treatments. This paper describes a method for the calibration of CO/CO2 monitors used for periodic inspections of vehicles in cites. The calibration was performed in the selected ranges: 900 - 12,000 µmol/mol for CO and 2000 - 20,000 µmol/mol for CO2. The traceability of the measurement results to the SI units was ensured by using certified reference materials from CO/N2 and CO2/N2 primary gas mixtures. The method performance was evaluated by assessing its linearity, accuracy, precision, bias, and uncertainty of the calibration results. The calibration data exhibited a strong linear trend with R² values close to 1, indicating an excellent fit between the measured values and the calibration lines. Precision, expressed as relative standard deviation (%RSD), ranged from 0.48 to 4.56% for CO and from 0.97 to 3.53% for CO2, staying well below the 5% threshold for reporting results at a 95% confidence level. Accuracy measured as percent recovery, was consistently high (≥ 99.1%) for CO and ranged from 84.90% to 101.54% across the calibration range for CO2. In addition, the method exhibited minimal bias for both CO and CO2 calibrations and thus provided a reliable and accurate approach for calibrating CO/CO2 monitors used in vehicle inspections. Thus, it ensures the effectiveness of exhaust emission control for better environment.

Validation of a Method for Characterization of Ethanol in Water by HS-GC-FID to Serve the Traceability of Halal Measurements

The determination of the ethanol content in food products is of fundamental importance for HALAL certification. In this work, an analytical method for the determination of ethanol in water by headspace gas chromatography with flame ionization detector (HS-GC-FID) has been developed and validated for the use in characterization of ethanol reference materials. The validation study was carried out in the linear calibration range 100 - 1500 mg/kg using the NIST SRM 2900, nominal 95.6%. The studied performance characteristics of the method were the limit of detection, LOD, the limit of quantification LOQ, selectivity, linearity, precision, recovery and bias. The validation results showed that the method is selective, precise, accurate and free from any significant bias. The LOD and LOQ were 1.27 and 3.86 mg/kg respectively and the estimated expanded uncertainty was 2% indicating that the method is fit for the purpose of certification of ethanol in water reference materials.

Indoor Formaldehyde Removal Techniques through Paints: Review

Due to its ability to cause illnesses and discomfort even at low concentrations, formaldehyde pollution of indoor air poses a significant risk to human health. Sources of formaldehyde in indoor environments include textiles, paints, wallpapers, glues, adhesives, varnishes, and lacquers;furniture and wooden products like particleboard, plywood, and medium-density fiberboard that contain formaldehyde-based resins;shoe products;cosmetics;electronic devices;and other consumer goods like paper products and insecticides. According to the World Health Organisation, indoor formaldehyde concentrations shouldn’t exceed 0.1 mg/m3. The methods include membrane separation, plasma, photocatalytic decomposition, physisorption, chemisorption, biological and botanical filtration, and catalytic oxidation. Materials based on metal oxides and supported noble metals work as oxidation catalysts. Consequently, a paint that passively eliminates aldehydes from buildings can be developed by adding absorbents and formaldehyde scavengers to the latex composition. It will be crucial to develop techniques for the careful detection and removal of formaldehyde in the future. Additionally, microbial decomposition is less expensive and produces fewer pollutants. The main goal of future research will be to develop a biological air quality control system that will boost the effectiveness of formaldehyde elimination. The various methods of removing formaldehyde through paints have been reviewed here, including the use of mixed metal oxides, formaldehyde-absorbing emulsions, nano titanium dioxide, catalytic oxidation, and aromatic formaldehyde abating materials that can improve indoor air quality.

Solar-Driven Water Treatment: New Technologies, Challenges, and Futures

In this review, the new solar water treatment technologies, including solar water desalination in two direct and indirect methods, are comprehensively presented. Recent advances and applications of five major solar desalination technologies include solar-powered humidification–dehumidification, multi-stage flash desalination, multi-effect desalination, RO, and solar stills. Each technology’s productivity, energy consumption, and water production costs are presented. Also, common methods of solar water disinfection have been reviewed as one of the common and low-cost methods of water treatment, especially in areas with no access to drinking water. However, although desalination technologies have many social, economic, and public health benefits, they are energy-intensive and negatively affect the environment. In addition, the disposal of brine from the desalination processes is one of the most challenging and costly issues. In this regard, the environmental effects of desalination technologies are presented and discussed. Among direct solar water desalination technologies, solar still technology is a low-cost, low-tech, and low-investment method suitable for remote areas, especially in developing countries with low financial support and access to skilled workers. Indirect solar-driven water desalination technologies, including thermal and membrane technologies, are more reliable and technically more mature. Recently, RO technology has received particular attention thanks to its lower energy demand, lower cost, and available solutions to increase membrane durability. Disposal of brines can account for much of the water cost and potentially negatively affect the environment. Therefore, in addition to efforts to improve the efficiency and reduce the cost of solar technologies and water treatment processes, future research studies should consider developing new solutions to this issue.

Electrochemically and Ultrasonically-Enhanced Coagulation for Algae Removal

At the global level, the augmenting presence of harmful algae blooms constitutes important dares to water treatment plants (WTPs). In WTPs, coagulation remains the primary process of the applied procedure to treat algae-contaminated water. Such a chemical process influences the following techniques;thus, regulating coagulation parameters to eliminate algae at the maximum degree without provoking cell deterioration is more than crucial. This work aims to review coagulation-founded methods for algae elimination. First, investigations concentrating on algae elimination using the chemical process are discussed. The introduction presents the widespread algae encountered in the water treatment field. Then, habitually utilized experimental techniques and emerging methods in coagulation investigations are summarized with typical findings. Next, the newest expansions in improved algae elimination, launched by electrochemically and ultrasonically-enhanced coagulation, are discussed. Workable thoughts for applying coagulation to eliminate algae in WTPs are also debated. The paper finishes by defining restrictions and dares related to the present literature and suggesting trends for subsequent studies. The charge neutralization mechanism efficiently removes solubilized microcystins (MCs), and enhanced coagulation configuration is also found to be more efficient for their removal. However, considerations should be taken to avert that the acid introduction has no unwanted effect in killing algae treatment to avoid the solubilized MCs level elevation. If such techniques are well-optimized and controlled, both algae and solubilized MCs could be efficaciously removed by ultrasound-enhanced coagulation and electrocoagulation/electrooxidation.

Xanthan Gum—Bio-Based Raw Material for Wood Adhesive

Due to their lower environmental impact, ease of accessibility, low cost, and biodegradability, bio-renewable sources have been used extensively in the last several decades to synthesize adhesives, substituting petrochemical-based adhesive. Vegetable oils (including palm, castor, jatropha, and soybean oils), lactic acid, potato starch, and other bio-renewable sources are all excellent sources for the synthesis of adhesives that are being taken into consideration for the synthesis of “eco-friendly” adhesives. Due to their widespread use, accessibility, affordability, and biodegradability, biobased raw materials like carbohydrates used to synthesize wood and wood composite adhesive have gradually replaced petrochemical-based adhesive. Recently, xanthan gum, a naturally occurring polymer, has drawn the interest of scientists as a potentially petroleum source replacement. It possesses specific rheological characteristics, excellent water solubility, and stability to heat, and can be used as a binder, thickener, suspending agent, and stabilizer. Xanthan gum increases the adhesive strength in addition to increasing the viscosity of water-soluble adhesives. This article discusses xanthan gum as a potential substitute for traditional raw materials derived from petroleum that is used as a raw material for adhesives.

Production of Biogas from Olive Mill Waste Waters Treated by Cow Manure

The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols).

On Sustainable Production of CaCO3 via Monohydrocalcite—A Carbon Capture and Mineralisation Product from Waste Brines

This study investigated the conversion of monohydrocalcite (MHC) to anhydrous calcium carbonate. The primary material, MHC, was produced from waste brines containing Ca and Mg ions, reacted with sodium carbonate, which may serve in the carbon capture and mineralisation approach. Two different approaches to the conversion were studied: 1) the conversion of MHC conversion to anhydrous calcium carbonates in air (under ambient conditions);2) the identification of conversion conditions which could be adapted for potential industrial application. The former focused on the effects of the synthesis system conditions of the primary material on the aragonite conversion process and the resulting aragonite morphology, whereas the latter covered the factors that accelerate conversion and influence the resulting morphology. The paper also discusses instances where MHC converts to the more stable polymorph, calcite. It was found that conditions leading to the polymorphic and morphological selection of converted minerals were temperature and humidity dependant.

Synthesis of Microcrystalline Cellulose—Polyvinyl Alcohol Stabilized Polyvinyl Acetate Emulsion

Polyvinyl alcohol (PVA) colloid stabilized Polyvinyl acetate (PVAc) based wood adhesive has poor performance in highly humid conditions. Currently, the addition of natural fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive in highly moist conditions. Microcrystalline cellulose (MCC) are strong renewable, bio-based material and has great potential in a reinforcement of the polymeric matrix. Hence, the present work investigates the applicability of microcrystalline cellulose incorporated 3% and 5% in situ emulsion polymerization PVAc wood adhesives. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with different proportions of MCC were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was increased by increasing the concentration of MCC. The mechanical properties like tensile strength of adhesives with MCC were measured by universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that MCC can improve bonding strength as compared to PVAc Homo based adhesive in the wet condition which was validated through a contact angle study. The hardness of PVAc films were also changed positively by the addition of MCC. Here, we studied the effect of the addition of different concentrations of MCC materials in situ polymerization of PVAc on their performance properties.

Environmentally Friendly Room Temperature Synthesis of 1-Tetralone over Layered Double Hydroxide-Hosted Sulphonato-Salen-Nickel(II) Complex

1-Tetralone, a useful synthetic intermediate in the manufacture of pharmaceuticals, agrochemicals and dyes, can be prepared by liquid phase catalytic oxidation of tetralin. Selective oxidation of tetralin to 1-tetralone is still a big challenge with low-temperature processes using environmentally friendly routes even after decades of research. Herein, we demonstrate room-temperature oxidation of tetralin to 1-tetralone over layered double hydroxide-hosted sulphonato-salen-nickel(II) complex, LDH-[Ni-salen]. The layered double hydroxide-hosted sulphonato-salen-nickel(II) compound was characterized by powder X-ray diffraction, Fourier transform infrared spectrometer (FTIR), UV-Visible diffuse reflectance spectra, scanning electron microscopy (SEM) and elemental analysis. The theoretical calculations of free sulphonato-salen-nickel(II) complex using Density Functional Theory/CAM-B3LYP at the 6-311++ G(d,p) level of theory were also used to determine the orientation of the Ni-salen compound within the layered structure. The immobilized compound, LDH-[Ni-salen] was found to be an effective reusable catalyst for the oxidation of tetralin to 1-tetralone using a combination of trimethylacetaldehyde and molecular oxygen (14.5 psi) and at 25°C. At 45.5% conversion, tetralin was converted to 1-tetralone with 77.2% selectivity at room temperature and atmospheric pressure after 24 h. The catalyst recycles test and hot filtration experiment showed that oxidation proceeded through Ni(II) sites in LDH-[Ni-salen]. The catalysts were reused several times without losing their catalytic activity and selectivity. The present results may provide a convenient strategy for the preparation of 1-tetralone using layered double hydroxide-based heterogeneous catalyst at ambient temperature for industrial application in near future.

Wood Density Determination with the Perspective to Decarbonisation of Tropical Forest Species from the Luki Biosphere Reserve in the Democratic Republic of the Congo

Specimens of the forest species such as Pentaclethra macrophylla, Petersianthus macrocarpus, Pycnanthus angolensis and Terminalia superba have been sampled from LUKI Biosphere reserve in the Democratic Republic of the Congo in order to determine their wood density with the perspective to decarbonisation. These parameters have been found out experimentally utilizing a drying technique in an oven including techniques of immersion in an Erlenmeyer full of water. The corresponding results indicated that the four species wood density is respectively 0.85, 0.80, 0.77 and 0.51. These preliminary results will be useful in our ongoing project on carbon dioxide absorption capacity of Congo rainforest tree species.

Validation of a Method for the Measurement of Caffeine in Water by HPLC-UV

For the production of a reference material from caffeine solution, one of the methods of characterization was HPLC-UV since caffeine is very sensitive to the UV. In this work, a batch solution of caffeine in water reference material of 1000 mg/kg has been gravimetrically prepared using a calibrated analytical balance. A sample of this solution was diluted to 25 mg/kg for measurement by HPLC-UV in the range 10 - 50 mg/kg. The chromatographic separation was carried out by C-18 column and a mobile phase assembled of 75% water and 25% methanol (v:v). The detection was made by the UV detector at 275 nm. The validation of this analytical method was carried out in accordance with requirements of the EURACHEM and ICH guidelines. The selectivity, linearity, accuracy, precision and trueness (recovery and bias) of the method were studied. The validation results proved that the method is fit-for-purpose of measuring the caffeine concentration in water in the range 10 - 50 mg/kg using HPLC-UV.

Virus Removal by Iron Coagulation Processes

Waterborne viruses account for 30% to 40% of infectious diarrhea, and some viruses could persevere for some months in nature and move up to 100 m in groundwater. Using filtration setups, coagulation could lessen virus charges as an efficient pre-treatment for reducing viruses. This work discusses the present-day studies on virus mitigation using coagulation in its three versions i.e., chemical coagulation (CC), enhanced coagulation, and electrocoagulation (EC), and debates the new results of virus demobilization. The complexity of viruses as bioparticles and the process of virus demobilization should be adopted, even if the contribution of permeability in virus sorption and aggregation needs to be clarified. The information about virion permeability has been evaluated by interpreting empirical electrophoretic mobility (EM). No practical measures of virion permeability exist, a clear link between permeability and virion composition and morphology has not been advanced, and the direct influence of inner virion structures on surface charge or sorption has yet to be conclusively demonstrated. CC setups utilizing zero-valent or ferrous iron could be killed by iron oxidation, possibly using EC and electrooxidation (EO) methods. The oxidants evolution in the iron oxidation method has depicted promising findings in demobilizing bacteriophage MS2, even if follow-up investigations employing an elution method are needed to secure that bacteriophage elimination is related to demobilization rather than sorption. As a perspective, we could be apt to anticipate virus conduct and determine new bacteriophage surrogates following subtle aspects such as protein structures or genome size and conformation. The present discussion’s advantages would extend far beyond an application in CC—from filtration setups to demobilization by nanoparticles to modeling virus fate and persistence in nature.

Certification of a Multicomponent Reference Material from Natural Gas Mixture by Gravimetry and Dual GC-FID/TCD System

Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measurement of its composition is of fundamental importance for trade reasons. To improve the quality of NG gas measurements, certified reference materials (CRMs) should be used for calibration of measuring equipment in order to ensure the traceability of the measurement results to the SI units. For the traceability purpose, a multicomponent natural gas mixture was prepared gravimetrically as a reference material according to ISO 6142 from pure helium, hydrogen, n-pentane, i-pentane, n-butane, i-butane, propane, ethane, hexane, methane and nitrogen. The preparation was done in two dilution steps in 5 L aluminum cylinders. The calculated mole fractions and associated uncertainties of natural gas components were verified by a dual GC-FID/TCD system in accordance with ISO 6143 calibrated by a series of primary gas mixtures (CRMs) produced by an NMI. The results obtained by gravimetry and by GC measurements have been checked for compatibility as required by ISO 6142 and were found in very good agreement. Details of the preparation and calculation of the mole fractions and uncertainties of all gas components are explained in this article.

Development of a Certified Reference Material from Caffeine Solution for Assuring the Quality of Food and Drug Measurements

Caffeine intake by pregnant women, adults and children can be harmful to the health of all particularly fetuses if the intake exceeds the permissible limits. Therefore, it is of fundamental importance to measure its concentration accurately using certified reference materials (CRMs). In the literature, no scientific details are published about the certification of caffeine standard solutions, and therefore, the present article covers this gap. A batch of caffeine solution was prepared in concentration of 1000 mg/kg and bottled. Homogeneity and stability of the candidate reference material were assessed by HPLC-UV and the results showed that the material is homogenous and stable enough. Characterization of the caffeine reference material was performed by HPLC-UV, LC-MS/MS and UV-VIS-NIR spectrophotometer in three different days and the characterization uncertainty was estimated in accordance with the requirements of ISO GUM. The certified value (999.86 ± 8.57 mg/kg) was derived as a weighted mean from the gravimetry and the three characterization methods and the certified uncertainty was calculated according to ISO Guide 35. The produced CRM is of strong interest to the food and drug analytical laboratories for the validity and credibility of their caffeine measurement results.

Environmentally Friendly Chitosan-Based Wood/Wood Composite Adhesive: Review

Due to the world’s energy issues and dependency on petroleum resources, focus has switched to finding new, sustainable raw material sources for wood adhesives. Renewable biopolymers would gradually replace petroleum and natural gas as the primary raw materials used in wood adhesives. Chitosan is a biomass substance having a lot of reserves. Chitosan is one of the most fascinating biopolymers in the adhesive sector because of its potential qualities for adhesive applications, such as biodegradability, biocompatibility, and non-toxicity. Chitosan and its derivatives have so garnered considerable interest in a wide range of adhesive applications. However, its adhesive strength is insufficient to glue wood under normal, humid conditions. There has been a lot of study done on how to make chitosan-based adhesives more cohesive and water resistant. In order to effectively use chitosan-based wood glue in wood/wood composite adhesive that gives comparable performance to synthetic adhesives, numerous new ways have been developed. It has been modified by the addition of various cross-linkers, including aldehydes like glyoxal glutaraldehyde etc., epoxy compounds, blended with other polymers, different acids and chitosan grafted onto vinyl acetate. In the production of wood composites, chitosan can also scavenge formaldehyde. This review of chitosan-based adhesives focuses on various cross-linkers for chitosan modification in order to improve the properties of chitosan-based wood adhesives.

Optimization and Thermodynamic Studies of Lead (II) and Cadmium (II) Ions Removal from Water Using Musa acuminate Pseudo-Stem Biochar

We recently found out that water from the Ugandan stretch of the Kagera transboundary river (East Africa) is contaminated with lead (Pb2+) and cadmium (Cd2+) ions at levels that are above permissible limits in drinking water. Because lignocellulosic biomass-based adsorbents have been explored for the remediation of metal ions from water, this study investigated the potential of Musa acuminata pseudo-stem (MAPS) biochar for the remediation of Pb2+ and Cd2+ ions from water. Batch adsorption experiments were performed to optimize the adsorption conditions while the isotherms were analyzed using Freundlich and Langmuir models. Results showed that the maximum adsorption capacity at equilibrium was 769.23 mg/g and 588.23 mg/g for Pb2+ and Cd2+ ions, respectively. Langmuir isotherm model provided the best fit for the data, and it was favorable since all r2 values (Cd2+ = 0.9726 and Pb2+ = 0.9592) were close to unity. Gibb’s free energy change was found to be negative for both metals, implying the feasibility of the adsorption process. Correspondingly, the enthalpy change was positive for both metal ions which revealed that the adsorption process was endothermic and it occurred randomly at the solid-liquid interface. These results suggested that biochar from MAPs could be utilized for the removal of Pb2+ and Cd2+ from polluted water in the Kagera transboundary river to make it suitable for domestic use. Further studies should consider chemical modification of the biochar as well as characterization to examine the chemical nature of the biochar.

Bismuth (III) Triflate Catalyzed Multicomponent Synthesis of 2,4,5-Trisubstituted Imidazoles

Substituted imidazoles are of interest because of their useful biological activities. While several methods have been developed for the synthesis of such compounds, some of the reported methods utilize corrosive or toxic catalysts. We report a bismuth (III) triflate catalyzed multicomponent synthesis of 2,4,5-trisubstituted imidazoles. Bismuth (III) compounds are attractive from a green chemistry perspective because they are remarkably non-toxic and non-corrosive. Multicomponent syntheses save time and generate less waste.

Wastewater Treatment Trial by Double Filtration on Granular Activated Carbon (GAC) Prepared from Peanut Shells

The aim of this work is the purification of wastewater by double filtration on granular activated carbon prepared from peanut shells. The samples of carbonized peanut shells were activated with 35% sulfuric acid and finally, we proceeded to the purification tests on double filtration of wastewater. Granular activated carbons (GAC) were very effective for the treatment of turbidity, dissolved oxygen, suspended solids, iron, COD and BOD5 but the best results were observed with nitrite, nitrate and phosphate. However, the second filtration was the most efficient while the lowest rates were observed for pH (17.91% on average), and conductivity (29.71% on average). In addition, this work has allowed increasing the dissolved oxygen by more than 50.16% at the exit of the first filter and more than 105.36% at the exit of the second filter. This study shows that granular activated carbon prepared from peanut shells could be a credible alternative for developing countries in the control of pollution and environmental protection.

Functionalization of Polypropylene with High Dielectric Properties: Applications in Electric Energy Storage

Biaxial-oriented polypropylene (BOPP) thin films are currently used as dielectrics in state-of-the-art capacitors that show many advantages, such as low energy loss and high breakdown strength, but a limited energy density ( 600 MV/m. The PP-OH dielectric demonstrates a linear reversible charge storage behavior with high releasing energy density > 7 J/cm3 (2 - 3 times of BOPP) after an applied electric field at E = 600 MV/m, without showing any significant increase of energy loss and remnant polarization at zero electric field. On the other hand, a cross-linked polypropylene (x-PP) exhibits an ε ~ 3, which is independent of a wide range of temperatures and frequencies, slim polarization loops, high breakdown strength (E = 650 MV/m), narrow breakdown distribution, and reliable energy storage capacity > 5 J/cm3 (double that of state-of-the-art BOPP capacitors), without showing any increase in energy loss.