Using walnut shells as low-cost adsorbent materials in an anaerobic filter medium of a De-centralized wastewater treatment system (DEWATS)

The flow of unprocessed sewage through municipal sewers is a great source of water contamination. This study aims to observe the pollutants removal efficiencies of walnut shells as an efficient low-cost adsorbent material compared to gravel materials as an anaerobic filter medium. Two models of the De-Centralized Wastewater Treatment System (DEWATS) were constructed. The wastewater flowing from toilets and handwashing places was connected to anaerobic filters filled with walnut shells and gravel. The efficiency of both filter media in the removal of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), nitrate (NO3), and phosphate (PO43), pH and temperature were observed at the influent of the settler tank and then at the effluent of the collection tank (CT). Temperature and pH were within the acceptable limit of wastewater discharge. The results also indicated that the walnut shells filter media was more efficient at removing organic pollutants (TSS 94%, BOD5 88%, COD 85%, Nitrate 57%, phosphate 46%, and TDS 29%) than the gravel (TSS 81%, BOD5 82%, COD 84%, Nitrate 35%, phosphate 38%, and TDS 26%) at the successive stages. The average removal efficiency of the walnut shell was 88% while in the gravel case, it was 83%. The removal efficiency of walnut shell filters was extensively better over the complete experiment compared to gravel filters for the removal of pollutants, representing the high sorption capability of the walnut shell material. The results of this study show that the walnut shells may be a very useful substitute for other conventional fillers for anaerobic treatment in the anaerobic filter of DEWATS.

Cobalt availability in the soil plant and animal food chain: a study under a peri-urban environment

Cobalt metal is considered as an essential trace element for the animals. Present investigation was undertaken in the peri-urban area to analyze the cobalt availability in animal food chain by using different indices. Cow, buffalo and sheep samples along with forage and soil samples were collected from the three different sites of District Jhang and analyzed through atomic absorption spectrophotometer. Cobalt values differed in soil samples as 0.315-0.535 mg/kg, forages as 0.127-0.333 mg/kg and animal samples as 0.364-0.504 mg/kg. Analyzed cobalt concentration in soil, forage and animal samples was found to be deficient in concentration with respect to standard limits. Soil showed the minimum cobalt level in Z. mays while maximum concentration was examined in the forage C. decidua samples. All indices examined in this study has values lesser than 1, representing the safer limits of the cobalt concentration in these samples. Enrichment factor (0.071-0.161 mg/kg) showed the highly deficient amount of cobalt enrichment in this area. Bio-concentration factor (0.392-0.883) and pollution load index (0.035-0.059 mg/kg) values were also lesser than 1 explains that plant and soil samples are not contaminated with cobalt metal. The daily intake and health risk index ranged from 0.00019-0.00064 mg/kg/day and 0.0044-0.0150 mg/kg/day respectively. Among the animals, cobalt availability was maximum (0.0150 mg/kg/day) in the buffaloes that grazed on the C. decidua fodder. Results of this study concluded that cobalt containing fertilizers must be applied on the soil and forages. Animal feed derived from the cobalt containing supplements are supplied to the animals, to fulfill the nutritional requirements of livestock.

Pyrolysis of Aesculus chinensis Bunge Seed with Fe2O3/NiO as nanocatalysts for the production of bio-oil material

The rapid thermal cracking technology of biomass can convert biomass into bio-oil and is beneficial for industrial applications. Agricultural and forestry wastes are important parts of China's energy, and their high-grade utilization is useful to solve the problem of energy shortages and environmental pollution. To the best of our knowledge, the impact of nanocatalysts on converting biowastes for bio-oil has not been studied. Consequently, we examined the production of bio-oil by pyrolysis of Aesculus chinensis Bunge Seed (ACBS) using nanocatalysts (Fe₂O₃ and NiO catalysts) for the first time. The pyrolysis products of ACBS include 1-hydroxy-2-propanone (3.97%), acetic acid (5.42%), and furfural (0.66%). These chemical components can be recovered for use as chemical feedstock in the form of bio-oil, thus indicating the potential of ACBS as a feedstock to be converted by pyrolysis to produce value-added bio-oil. The Fe₂O₃ and NiO catalysts enhanced the pyrolysis process, which accelerated the precipitation of gaseous products. The pyrolysis rates of the samples gradually increased at DTG_max, effectively promoting the catalytic cracking of ACBS, which is beneficial to the development and utilization of ACBS to produce high valorization products. Combining ACBS and nanocatalysts can change the development direction of high valorization agricultural and forestry wastes in the future.

Facile synthesis of gold-silver/copper sulfide nanoparticles for the selective/sensitive detection of chromium, photochemical and bactericidal application

In this project, bimetallic Au-Agnanoparticles/CuS nanoparticles were prepared via simple hydrothermal methods, which were used as highly efficient material for Cr (III) detection, photocatalytic, and biological process. The Au-Ag/CuS nanoparticles was studied via UV-visible spectroscopy, field-emission scanning electron microscopy, Dynamic light scattering, and X-ray diffraction. The zeta potential and effective size of Au-Ag/CuS nanoparticles was -32.1 mV and 25 nm respectively. The response time of Cr (III) ions interaction was 2 min. The lowest detection of Cr (III) by Au-Ag/CuS nanoparticles was 0.5 nM. The Au-Ag/CuS nano catalyst was applied to decomposition of drug under visible lamp irradiation. The photo degradation response of drug was 100.0% in 30 min irradiation. The particles exhibited excellent antibacterial activities.

Fabrication of silver phosphate-ilmenite nanocomposites supported on glycol chitosan for visible light-driven degradation, and antimicrobial activities

Recently, photo-degradation process under ultraviolet-light irradiation is being used as a substantial treatment method for the removal of environmental pollution. In this study, a silver phosphate-ilmenite (Ag₃PO₄-FeTiO₃) hetero structure supported on glycol chitosan catalyst was completely prepared, also, and its structural, and optical properties were characterized. Meantime, scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and UV-vis spectra were applied. The Ag₃PO₄-FeTiO₃/glycol chitosan catalyst was used to degrade metronidazole under visible-light irradiation. The degradation rate of metronidazole in 25 min by Ag₃PO₄-FeTiO₃/glycol chitosan nanocomposites was found to be 99.2% under UV light irradiation, which was higher than that by Ag₃PO₄-FeTiO₃ (72.24%) and FeTiO₃ (35.5%), respectively. The active species trapping test of Ag₃PO₄-FeTiO₃/glycol chitosan indicated that ·OH and ·O₂^- participated during the reaction. The diffusion method was evaluated to appraise the bactericidal activity of the synthesized nanomaterials when tested against both Staphylococcus aureus and Escherichia coli bacteria, with or without LED-light irradiation. The antibacterial tests show higher inhibition zones under light illumination as compared to dark conditions. The antifungal properties of the prepared nanomaterials were analyzed by fungi (Aspergillus niger, and Fusarium solani) using disc diffusion analysis. It was confirmed that the prepared nanomaterials have the best antifungal agent as compared to the standard antibiotics. When the Ag₃PO₄-FeTiO₃/glycol chitosan was used, the amount of inhibition zone was enhanced.

Bacterial-mediated synthesis of silver nanoparticles and their significant effect against pathogens

Silver nanoparticles are potent antimicrobials and could be used as a promising alternative of conventional antibiotics. The aim of this study was to isolate bacteria from soil that have ability to produce AgNPs by secondary metabolite activity and their elucidation against human pathogens. These strains Escherichia coli, Exiguobacterium aurantiacumm, and Brevundimonas diminuta with NCBI accession number MF754138, MF754139, and MF754140 respectively were grown for secondary metabolite production. The nanoparticles were confirmed and characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Three parameters, temperature, pH, and AgNO3 concentration, were used to optimize the production of silver nanoparticles. Antimicrobial potential of these nanoparticles was addressed on the Muller-Hinton Agar, and their zones of inhibitions were measured. TEM analysis revealed the size and shape of the silver nanoparticles. All types of AgNPs were spherical in shape; their size range is from 5 to 50 nm. The findings of optimization study showed the maximum production of silver nanoparticles at the pH 9, temperature 37 °C, and 1 mM AgNO3 concentration. All the strains exhibited the great potential as antimicrobial agents against MRSA and several other MDR bacteria with minimum 10 mm to maximum 28 mm zone of inhibition. It was concluded that the present study is an eco-friendly approach for the synthesis of AgNPs that will be beneficial to control the nosocomial infections triggered by MRSA and other human pathogens.

As(III) and As(V) removal mechanisms by Fe-modified biochar characterized using synchrotron-based X-ray absorption spectroscopy and confocal micro-X-ray fluorescence imaging

Batch experiments followed by solid-phase analyses were conducted to explore As(III) and As(V) removal mechanisms by Fe-modified biochars (FeBC) pyrolyzed at different temperatures (300, 600, and 900 °C). Arsenic removal by FeBC, best described by pseudo-second order kinetic and Langmuir isotherm models, increased from 73.8 to 99.9% for As(III) and 86.8 to 99.9% for As(V) as the pyrolysis temperature increased. The addition of calcite enhanced the removal efficiency (all > 99%). Confocal micro-X-ray fluorescence imaging (CMXRFI) analyses indicated As co-located with Fe and diffused deeper into the particles as the pyrolysis temperature increased. For As(III)-spiked systems, X-ray absorption near-edge structure (XANES) data indicated 20.2 to 81.5% of As(III) was oxidized to As(V) as the pyrolysis temperature increased; an increase of oxidation efficiency was observed after adding calcite. For As(V)-spiked systems, no As(V) reduction was observed. Overall, As(III/V) removal using FeBC was affected by the spatial distribution and species of As.

Synhesis of Silver and Copper Nanoparticles from Plants and Application as Adsorbents for Naphthalene decontamination

Synthesis of nanoparticles by using plants is biological method of synthesis that is ecofriendly as well as low cost. Naturally available precursor in the form of plants extract is used. In our research we used three different plants such as Aloe barbedensis, Azadirachta indica and Coriandrum sativum that are easy to cultivate and also available everywhere. By using above mentioned plants we synthesize two types of nanoparticles one is (Ag-NPs) and other one is (Cu-NPs). Chemical method of nanoparticles synthesis have hazardous to health as well as have environmental threats but as comparison with biological method of nanoparticles synthesis is very environment friendly also safe in use. FTIR (Fourier Transform Infrared) spectroscopy analysis and UV-Visible Spectrophotometer are used for characterization. Our research work is actually based on wastewater remediation by using silver and copper nanoparticles. Water that is contaminated with naphthalene used, further decontaminated and purify by using nanoparticles. Different batch experiments are conducted to check the efficiency of these synthesized nanoparticles by using naphthalene (PAHs) as removal area. 98.81% removal is higher by using plant Azadirachta indica and least adsorption power is in case of Coriandrum sativum that is 95.29%. At the end, kinetic and equilibrium study applied.

The level of allergens in dust samples collected from selected schools in Shiraz, Iran and its asthma-risk implications

BACKGROUND

Both home and school are important places where children are exposed to various indoor allergens. This study aimed to identify the profile of indoor allergens in schools and its impact on asthma development.

METHODS

A total of 104 classrooms from 52 schools were selected for dust collection during the fall of 2017. The levels of indoor allergens including dust mite (Der f1, Der p1), cat (Fel d1), cockroach (Bla g1) and mouse (Mus m1) were measured by enzyme linked immunosorbent assay (ELISA). The diagnosis of asthma was made in all students of the selected classes by the allergist. The collected data were analyzed using SPSS version 21.0.

RESULTS

Out of 2816 students in the selected classes, 180 students were involved with asthma. Students were mostly exposed to Bla g1 (83.1%), followed by Der f1 (51.5%), Mus m 1 (45.5%), Der p1 (8.9%) and Fel d1 (7.9%) in the dust collected from 101 classrooms. Although levels of all studied allergens in the settled dust of the classrooms were low, there was a relationship between Fel d1 in the classroom dust and development of asthma.

CONCLUSION

This study showed considerable levels of cockroach allergens in schools. Exposure to cat allergen in our schools played an important role in asthma development; further school-based investigations require evaluating the role of classroom allergen on asthma development.

Artificial neural network model to predict transport parameters of reactive solutes from basic soil properties

Measurement of solute-transport parameters through soils for a wide range of solute- and soil-types is time-consuming, laborious, expensive and practically impossible. So, indirect methods for estimating the transport parameters by pedo-transfer functions are now advancing. This study developed and evaluated an Artificial Neural Network (ANN) model for estimating the transport velocity (V), dispersion coefficient (D) and retardation factor (R) of NaAsO₂, Pb(NO₃)₂, Cd(NO₃)₂, C₉H₉N₃O₂ and CaCl₂ from the basic soil properties. Breakthrough data of the solutes were measured in 14 agricultural soils of Bangladesh by time-domain reflectometry (TDR) in repacked soil columns under unsaturated steady-state water-flow conditions. The transport parameters of the chemicals were determined by analyzing the solute breakthrough data. Bulk density (γ), organic carbon (OC), clay (C) content, pH, median grain diameter (D₅₀) and uniformity coefficient (C_u) of the soils were determined. An ANN model for V, D and R was developed by using data of eight soils, validated/tested with the data of five soils and verified with the data of one soil. Clay content and bulk density of the soils were the most sensitive input variables to the ANN model followed by other soil properties (OC, C, pH, D₅₀ and C_u). The model reliably predicted V, D and R with relative root-mean-square error (RRMSE) of 0.028-0.363, mean error (ME) of - 0.00004 to 0.0005, bias error (BOE%) of 0-0.003 and modeling efficiency (EF) of >0.99. Thus, the ANN model can significantly enhance prediction of pollution transport through soils in terms of cost and effort.

Design, preparation and evaluation of a high performance sensor for formaldehyde based on a novel hybride nonocomposite ZnWO3/rGO

The ultrasound wave assisted synthesis of a novel ZnWO₃/rGO hybrid nono composition (ZnWO₃/rGO HNC) as a high performance sensor for formaldehyde (FA) has been reported. Different techniques of analysis such as XRD, FE-SEM, TGA, XPS, HRTEM and BET were applied for morphological and spectroscopic characterization of the ZnWO₃/rGO HNC. The sensing evaluation of the constructed sensor showed high selectivity, sensitivity and a linear correlation between achieved responses and concentration of target gas (1-10 ppm) with R² = 0.993 at temperature of 95 °C. The determination of FA was validated and performed using gas chromatography-mass spectrometry combined by solid phase micro-extraction after derivatization with O-(2,3,4,5,6-pentafluoro-benzyl)-hydroxylamine hydrochloride. Validation was carried out in terms of limit of detection linearity, precision, and recovery. The mechanistic evaluation of sensing behavior of the ZnWO₃/rGO HNC was interpreted based on large specific surface area (SSA) to volume, mesoporous structure and the heterojunction between rGO and ZnWO₃ at the interface between the rGO and ZnWO₃.

Effects of Size and Aggregation/Agglomeration of Nanoparticles on the Interfacial/Interphase Properties and Tensile Strength of Polymer Nanocomposites

In this study, several simple equations are suggested to investigate the effects of size and density on the number, surface area, stiffening efficiency, and specific surface area of nanoparticles in polymer nanocomposites. In addition, the roles of nanoparticle size and interphase thickness in the interfacial/interphase properties and tensile strength of nanocomposites are explained by various equations. The aggregates/agglomerates of nanoparticles are also assumed as large particles in nanocomposites, and their influences on the nanoparticle characteristics, interface/interphase properties, and tensile strength are discussed. The small size advantageously affects the number, surface area, stiffening efficiency, and specific surface area of nanoparticles. Only 2 g of isolated and well-dispersed nanoparticles with radius of 10 nm (R = 10 nm) and density of 2 g/cm³ produce the significant interfacial area of 250 m² with polymer matrix. Moreover, only a thick interphase cannot produce high interfacial/interphase parameters and significant mechanical properties in nanocomposites because the filler size and aggregates/agglomerates also control these terms. It is found that a thick interphase (t = 25 nm) surrounding the big nanoparticles (R = 50 nm) only improves the B interphase parameter to about 4, while B = 13 is obtained by the smallest nanoparticles and the thickest interphase.

The fate and transport of arsenic species in the aquatic ecosystem: a case study on Bestari Jaya, Peninsular Malaysia

The field of arsenic pollution research has grown rapidly in recent years. Arsenic constitutes a broad range of elements from the Earth's crust and is released into the environment from both anthropogenic and natural sources due to its relative mobility under different redox conditions. The toxicity of arsenic is described in its inorganic form, as inorganic arsenic compounds can leach into different environments. Sampling was carried out in the Bestari Jaya catchment while using a land use map to locate the site, and experiments were conducted via sequential extraction and inductively coupled plasma optical emission spectroscopy to quantify proportions of arsenic in the sediment samples. The results show that metals in sediments of nonresidual fractions, which are more likely to be likely released into aquatic environments, are more plentiful than the residual sediment fractions. These findings support the mobility of heavy metals and especially arsenic through sediment layers, which can facilitate remediation in environments heavily polluted with heavy metals.

Chemical speciation and bioavailability of rare earth elements (REEs) in the ecosystem: a review

Rare earths (RE), chemically uniform group of elements due to similar physicochemical behavior, are termed as lanthanides. Natural occurrence depends on the geological circumstances and has been of long interest for geologist as tools for further scientific research into the region of ores, rocks, and oceanic water. The review paper mainly focuses to provide scientific literature about rare earth elements (REEs) with potential environmental and health effects in understanding the research. This is the initial review of RE speciation and bioavailability with current initiative toward development needs and research perceptive. In this paper, we have also discussed mineralogy, extraction, geochemistry, analytical methods of rare earth elements. In this study, REEs with their transformation and vertical distribution in different environments such as fresh and seawater, sediments, soil, weathering, transport, and solubility have been reported with most recent literature along key methods of findings. Speciation and bioavailability have been discussed in detail with special emphasis on soil, plant, and aquatic ecosystems and their impacts on the environment. This review shows that REE gained more importance in last few years due to their detrimental effects on living organisms, so their speciation, bioavailability, and composition are much more important to evaluate their health risks and are discussed thoroughly as well.

Effects of Codonopsis pilosula water extract on MicroRNA expression profile in D-galactose-induced senile mice

This paper aims to observe and analyze effects of Codonopsis pilosula water extract on micro RNA (miRNA) expression profile in liver tissue of senile mice. The 110 Konminmice were randomly divided into five groups, including D-galactose-induced senile model group, normal control group, and low, middle and high dose intervention groups. Continuous modeling lasted 40 days. General symptoms and changes of body mass of the model mice were monitored and observed. The levels of serum glutamic pyruvic transaminase (ALT) and alkaline phosphatase (ALP) of mice were compared, and miRNA of differential expression during aging of D-galactose-induction and high-dose Codonopsis pilosula intervention was analyzed. The serum ALT and ALP levels in the aging model group were significantly higher than those in the normal control group (P<0.05). The serum ALT and ALP levels of Codonopsis pilosula intervention group were lower than those of aging model group, and decrease in ALP value of high dose intervention group was higher (P<0.05). The expression profile of miRNA in the aging model group was significantly different from that in normal control group and high-dose Codonopsis pilosula intervention group, and miRNA expression profile in high-dose Codonopsis pilosula intervention group was clustered with that in the normal control group. The differentially expressed miRNAs of D-galactose-induced senescence and Codonopsis pilosula anti-aging usually belong to 7 miRNA clusters. The target gene function of the differentially expressed miRNAs during senescence process was enriched in 29 signal pathways. There were 67 regulatory signal pathways in differentially expressed miRNA target genes during Codonopsis pilosula intervention. The effect of miRNA targeting may play an important role during D-galactose-induced senescence and Codonopsis pilosula anti-aging period.