Challenges on the recycling of cigarette butts Yousefi, Mahmood; Kermani, Majid; Farzadkia, Mahdi ...
Environmental science and pollution research international,
06/2021, Letnik:
28, Številka:
24
Journal Article
Recenzirano
Cigarette butt (CB) is a crucial litter in urban communities because it may contain various toxicants. Due to serious limitations on incinerating or landfilling CB, recycling of this hazardous waste ...is essential. The objective of this study was to investigate the most important challenges in CB collection and recycling. To this end, a search was done on Scopus, PubMed, and Web of Science by defining a search protocol and identifying appropriate keywords. At the end of the screening process, 52 appropriate papers were selected. In this review, all methods for the CB recycling were considered. This review showed that nine categorizations of different products have been produced from the recycling of CBs, but three important challenges were identified for the recycling of this hazardous waste. It should be noted that finding solutions to these challenges may be helpful in better management of CB as a toxic litter.
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•Fe3O4–WO3–APTES nanoparticles were used as a photocatalyst for Cr(VI) reduction.•FT-IR and SEM techniques proved the effective presence of an amino group.•LED/Fe3O4–WO3–APTES process ...was more efficient than LED/Fe3O4 or LED/WO3 process.•Photocatalytic reduction process can be described by the Langmuir–Hinshelwood model.
Cr(VI) was reduced from synthetic, real drinking waters and real electroplating wastewater using the Fe3O4–WO3-3-aminopropyltriethoxysilane nanoparticles, as a heterogeneous catalyst, in the presence of visible light. The nanocatalyst was prepared via a simple co-precipitation method. FT-IR and SEM techniques proved the effective presence of an amino group. Under the optimum conditions: pH=2, Cr(VI)0=10mg/L, citric Acid=10mg/L, and nanocatalyst dosage=6g/L, 99.96% of Cr(VI) was removed after 300 min. Approximately 82.96% of Cr(VI) in a real water sample was removed after 1440min under the optimal circumstances. Also, full treatment of electroplating wastewater was reached after 2880min.
Wheat straw, which is a carbon-rich precursor and a common agriculture waste in Sanandaj, was modified to produce hydrochar with high adsorption capacity by the hydrothermal carbonization (HTC) ...method. The hydrochars were tested as adsorbents to remove methylene blue (MB) from aqueous solution, and the effects of various interfering parameters, including pH, MB concentration, and adsorbent dosage, were investigated using artificial neural networks (ANNs) on adsorption modeling. Adsorption isotherms and kinetics were studied to explain the MB adsorption process. The prepared hydrochars were characterized using Brunauer–Emmett–Teller (BET), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDAX), and high-performance liquid chromatography (HPLC) instruments. The maximum MB removal efficiency achieved by hydrochar modified by KOH (0.1 M) and adsorption data fitted well with the Langmuir isotherm and pseudo-second-order kinetics. In terms of elemental composition, the hydrochar sample contained 52.19% carbon (C), 3.37% hydrogen (H), 0.1% nitrogen (N), 0.15% sulfur (S), and 35.66% oxygen (O). The ash content in the sample was 8.50%. The recorded hydrogen-to-carbon ratio (H/C) and oxygen-to-carbon ratio (O/C) indicated a shift towards humification, implying the influence of KOH addition during the hydrochar production process. Additionally, the specific surface area of the hydrochar, as measured by the BET method, was found to be 11.54 m²/g. Among the aromatics, a significant presence of hydroxymethylfurfural (HMF) was detected, with a concentration of 4.70 g/kg DM. The modeling results demonstrated that the concentration of MB had the most substantial impact on the predicted removal, followed by pH, adsorbent dosage, and contact time.
The aim of this research was to develop a simple and inexpensive process for reduction of Cr(VI) to Cr(III). Zinc oxide nanoparticles were synthesized with an easy co-precipitation procedure, and the ...addition of Cu
2+
doping agent effectively enhanced the Cr(VI) reduction in the presence of ultrasound (US). XRD, FT-IR, FE-SEM, EDX, VSM, and XPS were used to determine the structural specifications of the zinc oxide nanoparticles. Under optimal conditions such as pH 3, initial Cr(VI) content of 20 mg/L, and catalyst dosage of 0.8 g/L, the ultrasonic/Cu–ZnO process showed a higher sonocatalytic activity (96.83%) than ultrasonic/ZnO (67.36%) after 60 min. By increasing pH and Cr(VI) concentration, the removal efficacy of Cr(VI) declined. The experimental data was well described with the first-order kinetic model. When initial Cr(VI) concentration increased from 10 to 50 mg/L, the first-order rate constant declined from 0.2326 to 0.0019 min
−1
and electrical energy per order (
E
EO
) enhanced from 19.81 to 2425.26 kWh/m
3
. Also, the ultrasonic/Cu–ZnO system exhibited considerable sonocatalytic performance in Cr(VI) reduction in the presence of hydrogen peroxide and citric acid, and complete removal was achieved within 60 min. The presence of anions negatively affected Cr(VI) reduction. Complete reduction was attained when ultrasound was applied at a power of 100 W. The catalyst activity was well maintained up to six consecutive cycles. In addition, the removal efficiency was approximately 62 and 65% for field water and real electroplating wastewater samples, respectively.
The scale-up feasibility of oily sludge (OS) biodegradation from a culture-based medium to a new two-stage composting process bioaugmentated with an indigenous isolated strain was surveyed. First, ...the bacterial strain (Enterobacter hormaechei strain KA6) was isolated from OS, and then its ability in biomass production and oil degradation in culture-based medium was evaluated. Finally, the strain was used for bioaugmentation in composting reactors which included four in-vessel experiments with the initial total petroleum hydrocarbon (TPHs) concentrations between 10 and 30 g kg
-1
. The strain was added twice to the composting reactors which lasted 16 weeks including the primary composting stage (PCS) (first inoculation) and the secondary composting stage (SCS) (second inoculation). It was observed that the strain degraded 58.67, 74.79, 45.33, 10.66, and 5.92% of 1, 2, 3, 4, and 5% oil concentrations, respectively, in culture-based medium during 7 days. Regarding OS bioremediation in the composting experiments, a total TPH removal rate of 65.83–81.50% was also reached after the two-stage duration of 16 weeks. Due to the second bioaugmentation stage, the SCS showed higher TPH removal efficiency than the PCS. The study confirmed the effectiveness of the scaling-up of a culture-based medium to a composting process for treating OS.
Continuous anodic oxidation of azo dye C.I. Acid Red 18 by using PbO
2
electrode in aqueous solution was studied. To reach the best conditions of the process, the influence of various operating ...parameters such as pH, current density, hydraulic retention time (HRT) and dye concentration on the removal rate of chemical oxygen demand (COD) and color, as indexes showing the amount of efficiency, was investigated. The findings showed that, respectively, 99.9% and 80.0% of the dye and COD were removed (at optimized conditions). Mineralization current efficiency results indicated that at the beginning of the reaction mineralization occurred quickly at a low current density, whereas at high amounts the rate of mineralization the efficiency decreased. At the optimum conditions, the majority of COD was removed only with 38.2 kWh/kg COD of energy consumption in 120 min. By controlling HO•/dye concentration ratio via the parameters adjustment, particularly HRT and current density, this system can treat Acid Red 18 well even at high concentrations. Furthermore, the voltammetry study illustrated that electroactive intermediates created during the process were mineralized at current density of 8.6mA/cm
2
.
Background: Cockroaches play a role in the mechanical transmission of microbial pathogens. This study was designed to determine the isolated bacteria and their susceptibility to conventional ...antibiotics from brown-banded cockroach, Supella longipalpa, in Qom province, central Iran. Methods: In this cross-sectional study, brown-banded cockroaches were bred in an insectary and caught from hospitals of Qom. The samples were taken from the surface and alimentary canal and then cultured on microbial culture media; next, grown specimens were identified using differential culture media. Finally, after performing diagnostic tests and identifying the bacteria species, their susceptibility to various antibiotics was evaluated. Results: A total of 120 adult cockroaches from the insectary and hospitals were included in the study. Ten bacterial genera were found; nine were Gram-negative and one was Gram-positive. The genus Klebsiella, Enterobacter, Staphylococcus, Citrobacter and Hafnia were isolated only from the hospital strain. On the other hand, Pseudomonas and Escherichia from both groups and other species such as Salmonella, Proteus and Shigella were isolated only from laboratory strains. The highest antibiotic resistance among Gram-positive cocci and Gram-negative bacilli were 100.0% and 98.1% for ampicillin and Ceftazidime, respectively. Conclusion: The results of this study showed that various pathogenic bacteria harbored by brown-banded cockroaches. Moreover, it was found that most of these bacteria belong to the Enterobacteriaceae family, which can be pathogenic and thus threaten human health.
This study was conducted to evaluate the mineralization of activated sludge (MAS) by a facile and environmentally friendly electro-Fenton process (EFP). The effects of initial H
2
O
2
concentration, ...pH value, applied current density and operating time on MAS through determining the removal rate of chemical oxygen demand (COD) and total coliform (TC) were studied. 72% of COD was removed by indirect oxidation double-mediated based on the electro-generation of hydroxyl radical and active chlorine, under the following optimum conditions: 127mmol L
-1
of hydrogen peroxide, pH=3.0, 10 mA cm
-2
of DC current, 120min of operating time, and 0.22mol L
-1
of NaCl as the supporting electrolyte. Only in 10 min and pH 3.0 approximately 100% of TC was removed. The findings indicated that EFP can be applied efficiently for MAS by selecting appropriate operating conditions. The bottom line is that the process is entirely effective owing to the application of green oxidants (hydroxyl radical and active chlorine) and lack of being influenced by environmental situations, which can be introduced as an alternative to current conventional methods.
This study investigated the efficiency of hydrochar derived from hydrothermal fulvification of wheat straw in adsorbing malachite green (MG) dye. The characterizations of the hydrochar samples were ...determined using various analytical techniques like SEM, EDX, FTIR, X-ray spectroscopy, BET surface area analysis, ICP-OES for the determination of inorganic elements, elemental analysis through ultimate analysis, and HPLC for the content of sugars, organic acids, and aromatics. Adsorption experiments demonstrated that hydrochar exhibited superior removal efficiency compared to feedstock. The removal efficiency of 91 % was obtained when a hydrochar dosage of 2 g L−1 was used for 20 mg L−1 of dye concentration in a period of 90 min. The results showed that the study data followed the Freundlich isotherms as well as the pseudo-second order kinetic model. Moreover, the determined activation energy of 7.9 kJ mol−1 indicated that the MG adsorption was a physical and endothermic process that increased at elevated temperatures. The study also employed an artificial neural network (ANN), a machine learning approach that achieved remarkable R2 (0.98 and 0.99) for training and validation dataset, indicating high accuracy in simulating MG adsorption by hydrochar. The model's sensitivity analysis demonstrated that the adsorbent dosage exerted the most substantial influence on the adsorption process, with MG concentration, pH, and time following in decreasing order of impact.
Background: Tea is one of most frequently consumed beverages in the world. Only in Iran, around 12000 tons of tea is annually used. Besides, green tea, which is made from Camellia sinensis leaves and ...buds, is very popular among people. Although teas have health benefits, since they may be much drunk, they may pose a threat to consumers’ health because of absorbing various ions in their leaves. Unfortunately, there are a limited number of studies on the health effects of green teas. Methods: It was a cross-sectional study performed in 2021. In this research, the concentrations of ions: fluoride (F), chloride (Cl), nitrate (NO3 ), sulfate (SO4 ), and phosphate (PO4 ) in the six bestselling green tea brands, both loose and bag, in Iran were detected by means of ion chromatography. Results: The highest amounts of F, Cl, NO3 , SO4 , and PO4 in the brands were found to be, respectively, in 0.27310, 0.62103, 0.83533, 1.28067, and 1.1037 mg/L. The concentrations of the ions in the both loose and bag tea samples were different significantly. Also, the content of F in the all samples was lower than those acceptable levels suggested by different organizations. Conclusion: It was found that the concentration of the ions was by far lower than those have been introduced as the standard levels. Nonetheless, the water used for tea infusion may contain high levels of these compounds and its volume drunk every day is also very important.
