Efficient removal of ciprofloxacin from aqueous solution using Zn-C battery derived graphene oxide enhanced by hydrogen bonding, electrostatic and π-π interaction.

In this study, graphene oxide (GO) derived from waste Zinc-Carbon (Zn-C) batteries was proposed for the efficient removal of antibiotics from the aqueous solution. Ciprofloxacin (CIP) antibiotic was selected as a typical contaminants. GO was prepared via an economical and environment-friendly route by using carbon rods from waste Zn-C batteries as the precursor. Characterization techniques were applied to determine the properties of as prepared GO. Effects of pH, contact time, and adsorbent dose on the adsorption were explored, and an optimum condition was established. Adsorption equilibrium was established in just 20 min for maximum removal of CIP (99.0%) at pH 5.7 for the adsorbent dose of 20 mg L-1 and at the initial concentration of CIP 2.0 mg L-1. The rapid and efficient removal of CIP was greatly influenced by the electrostatic attractions, pi-pi interactions and hydrogen bonding on the surface and edge of GO which was also proved by density functional theory (DFT). Langmuir model showed the best fit among the isotherm models and the calculated maximum adsorption capacity (qm) was 419.62 mg g-1 at 30°C. The kinetic studies also revealed that the adsorption process followed the pseudo-second-order model. The endothermic and spontaneous nature of adsorption was evaluated in thermodynamic studies.

Spatiotemporal distribution, ecological risk assessment, and human health implications of currently used pesticide (CUP) residues in the surface water of Feni River, Bangladesh.

Spatiotemporal monitoring of pesticide residues in river water is urgently needed due to its negative environmental and human health consequences. The present study is to investigate the occurrence of multiclass pesticide residue in the surface water of the Feni River, Bangladesh, using an optimized salting-out assisted liquid-liquid microextraction (SALLME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized SALLME method was developed and validated following the SANTE/11312/2021 guidelines. A total of 42 water samples were collected and analyzed to understand the spatiotemporal distribution of azoxystrobin (AZ), buprofezin (BUP), carbofuran (CAR), pymetrozine (PYM), dimethoate (DMT), chlorantraniliprole (CLP), and difenoconazole (DFN). At four spike levels (n = 5) of 20, 40, 200, and 400 µg/L, the recovery percentages were satisfactory, ranging between 71.1 % and 107.0 % (RSD ≤13.8 %). The residues ranged from below the detection level (BDL) to 14.5 µg/L. The most frequently detected pesticide was DMT (100 %), followed by CLP (52.3809-57.1429), CAR (4.7619-14.2867), and PYM (4.7619-9.5238). However, AZ and BUP were below the detection limit in the analyzed samples of both seasons. Most pesticides and the highest concentrations were detected in March 2023, while the lowest concentrations were present in August 2023.Furthermore, ecological risk assessment based on the general-case scenario (RQm) and worst-case scenario (RQex) indicated a high (RQ > 1) risk to aquatic organisms, from the presence of PYM and CLP residue in river water. Human health risk via dietary exposure was estimated using the hazard quotient (HQ). Based on the detected residues, the HQ (<1) value indicated no significant health risk. This report provides the first record of pesticide residue occurrences scenario and their impact on the river environment of Bangladesh.

Method development of multi pesticide residue analysis in country beans collected from Dhaka, Bangladesh, and their dietary risk assessment.

The aim of the study was to develop a modified QuEChERS method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of five multi-class pesticides in country beans collected from Dhaka, Bangladesh. Pesticides were extracted using ACN, and to minimize the co-extraction matrix, optimized d-SPE cleanup was done using sorbents (GCB, PSA, and C18). In the calibration range, the method showed excellent linearity with a correlation coefficient of R2 ≥ 0.9990 both in solvent- and matrix-matched calibration. For the selected pesticides, average recoveries (at four spiking levels (n = 5) of 10, 20, 100, and 200 µg/kg) of 70-100 % were achieved with relative standard deviations (RSDs) ≤ 9.5 %. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.3333 to 1.3333 µg/kg and 1.0 to 4.0 µg/kg, respectively. The dietary risk assessment, in terms of hazard quotient (HQ), was calculated to assess consumers' health risks.

Corrigendum to "Enrichment, sources, and distributions of toxic elements in the farming land's topsoil near a heavily industrialized area of central Bangladesh, and associated risks assessment" [Heliyon 9 (4) 2023 e15078].

[This corrects the article DOI: 10.1016/j.heliyon.2023.e15078.].

Ultrafast and simultaneous removal of four tetracyclines from aqueous solutions using waste material-derived graphene oxide-supported cobalt-iron magnetic nanocomposites.

In this work, a graphene oxide-supported cobalt-iron oxide (GO/Co-Fe) magnetic nanocomposite was successfully synthesized using waste dry cells for the efficient and simultaneous removal of tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), and doxycycline (DTC) from aqueous solutions. The GO/Co-Fe nanocomposite was thoroughly characterized using Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and zeta potential analysis. This multi-faceted characterization provided clean insights into the composition and properties of the synthesized nanocomposite. The adsorption of tetracyclines (TCs) was systematically investigated by assessing the influence of critical factors, such as adsorbent dosage, contact duration, initial pH of the solution, initial concentration, and temperature. The GO/Co-Fe adsorbent showed high removal efficiencies of 94.1% TC, 94.32% CTC, 94.22% OTC, and 96.94% DTC within 30 s contact period. The maximum removal efficiency of TCs was found at a low adsorbent dose of 0.15 g L-1. Notably, this superior removal efficiency was achieved at neutral pH and room temperature, demonstrating the adsorbent's efficacy under environmentally viable conditions. The kinetic studies demonstrated that the adsorption process was fitted satisfactorily with the pseudo-second-order model. Additionally, the adsorption behaviour of TCs on the GO/Co-Fe adsorbent was assessed by isotherm models, Langmuir and Freundlich. The experimental data followed the Langmuir isotherm, signifying a monolayer adsorption mechanism on the surface of the adsorbent. The adsorption capacities (qm) of GO/Co-Fe for TC, CTC, OTC and DTC were determined to be 64.10, 71.43, 72.46 and 99.01 mg g-1, respectively. Importantly, the GO/Co-Fe adsorbent showed reusability capabilities. The super magnetic properties of GO/Co-Fe made it easy to use for several cycles. These results clearly establish GO/Co-Fe as an exceptionally effective adsorbent for the removal of TCs from aqueous systems, highlighting its great potentiality in water treatment applications.

Effects of microplastic and heavy metals on coral reefs: A new window for analytical research.

In the modern world, plastic trash has been recognized as a global issue, and studies on microplastics (MPs) in the marine and inland environments have previously been conducted. Marine ecosystems act as a bio-diverse ecosystem where coral reefs contribute to make a sound living of the coastal people by gathering natural resources. The current study indicates that MPs and heavy metals (HMs) accumulation to biofilm and organic matter through sedimentation, precipitation, adsorption, and desorption that may have potential effect on growth and development of coral reefs in the marine ecosystems. However, the knowledge of distribution, impact, mechanism, degradation, and association mechanisms between MPs and HMs in the natural environment may open a new window for conducting analytical research from an ecological viewpoint. The current study thus summarizes the types of marine samples with the analytical techniques, polymers of MPs, and their impact on corals and other marine biota. This study also identifies existing knowledge gaps and recommends fresh lines of inquiry in light of recent developments in MPs and HMs research on the marine ecosystems. Overall, the present study suggests a sustainable intervention for reducing MPs and HMs from the marine ecosystems by demonstrating their existence in water, sediment, fish, corals, and other biota, and their impending ecotoxicological impacts on the environment and human health. The impacts of MPs and HMs on coral reefs are critically assessed in this study in light of the most recent scientific knowledge, existing laws, and new suggestions to minimize their contamination in the marine ecosystems.

Evaluation of chlorine dioxide in liquid state and in gaseous state as virucidal agent against avian influenza virus and infectious bronchitis virus.

The antiviral activity of chlorine dioxide (ClO2) in liquid (ClO2 gas dissolved liquid) and gaseous state against avian influenza virus (AIV) and infectious bronchitis virus (IBV) was evaluated. To evaluate the effect of ClO2 in liquid state, suspension tests (10 ppm) and carrier tests in dropping / wiping techniques (100 ppm) were performed. In the suspension test, virus titers were reduced below the detection limit within 15 sec after treatment, in spite of the presence of an accompanying organic matter. In the carrier test by dropping technique, AIV and IBV were reduced to below the detection limit in 1 and 3 min, respectively. Following wiping technique, no virus was detected in the wiping sheets after 30 sec of reaction. Both viruses adhering to the carriers were also reduced by 3 logs, thereby indicating that they were effectively inactivated. In addition, the effect of ClO2 gas against IBV in aerosols was evaluated. After the exposure of sprayed IBV to ClO2 gas for a few seconds, 94.2% reduction of the virus titer was observed, as compared to the pre-treatment control. Altogether, hence, ClO2 has an evident potential to be an effective disinfectant for the prevention and control of AIV and IBV infections on poultry farms.

Evaluation of antimicrobial efficacies of chlorine dioxide gas released into the air towards pathogens present on the surfaces of inanimate objects.

The efficacy of ClO2 gas, as surface disinfectant at around 1,000 ppb against avian orthoavulaviruses type 1 (AOAV-1), infectious bronchitis virus (IBV), Escherichia coli (EC), and Salmonella Enteritidis (SE) was evaluated at the required level (≥99.9% reduction) on various surfaces. Exposing the surfaces to ClO2 gas for 1 hr reduced AOAV-1, except for rayon sheets which required 3 hr. However, 1 hr of exposure did not effectively reduced IBV titer. In the case of EC, glass plates and plastic carriers needed 1 hr of exposure, while rayon sheets required 2 hr. SE on rayon sheets required 1 hr exposure, but on the other tested surfaces showed inadequate reduction. Overall, ClO2 gas is an effective disinfectant for poultry farms.

Complete genome constellations of two bovine rotavirus A strains isolated in Japan reveal a unique T9 NSP3 genotype.

Full genome sequencing of two bovine rotavirus A (RVA) strains isolated in Japan in 2019 revealed two genotype constellations; one had a constellation of G8-P[1]-I2-R2-C2-M2-A3-N2-T9-E2-H3. Thereupon, genotype T9 carried by RVA/Bovine-tc/JPN/AH1041/2022/G8P[1], constitutes a rare NSP3 genotype, and only two unusual Japanese bovine RVA strains have thus far been reported to carry this genotype. The other RVA/Bovine-tc/JPN/AH1207/2022/G6P[5] strain possessed a constellation of G6-P[5]-I2-R2-C2-M2-A3-N2-T6-E2-H3. Phylogenetic analyses indicate that the majority of gene segments were most closely related to Japanese bovine RVAs, suggesting that both strains might have derived through multiple reassortment events from RVA strains circulating within Japanese cattle. The emergence of RVA strains in Japan and their reassortment with locally circulating atypical RVAs could have implications for current vaccination strategies.

Development and validation of a modified QuEChERS method coupled with LC-MS/MS for simultaneous determination of difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole in brinjal collected from fields and markets places to assess human health risk.

An effective and sensitive analytical method was developed to quantify the most common pesticide residues (difenoconazole, dimethoate, pymetrozine, and chlorantraniliprole) used for brinjal cultivation in Bangladesh. The quantification of the analytes was done using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted using a modified QuEChERS method and followed by purification with dispersive solid phase extraction (d-SPE) sorbents (PSA, GCB, and C18). Matrix-matched calibration with a regression coefficient R2 ≥ 0.9964 were used to minimize the brinjal matrix effect. The method was validated in quintuple (n = 5) at five different spiked levels (8-400 µg/kg) having recoveries in the range of 70.3-113.2% with relative standard deviations RSDs ≤6.8%, limits of detection (LOD) and limits of quantification (LOQ) was in the range of 0.15-0.66 µg/kg and 0.4-2.0 µg/kg, respectively, for the four analytes. A total 100 samples (50 samples directly from fields of Jessore district, Bangladesh and 50 samples from local market of Dhaka, Bangladesh) were collected to analyse the pesticides residue. The result showed that pesticides residue was found in both the field and market collected samples, 54% and 38%, respectively. The overall mean residue levels of four pesticides in field samples were significantly higher than those of market samples. Moreover, 20% of the field samples and 10% of the market samples had dimethoate residues, which were the most abundant among the four analytes and it ranged from 0.017 to 0.252 mg/kg. In terms of health risk assessments, dimethoate showed the highest estimated daily intake (EDI) and hazard quotient (HQ) values that are 3.02 × 10-5 mg/kg/day and 1.51%, respectively, in field samples. Till now, there have been no regulations or guidelines for the maximum admissible pesticide residue in Bangladesh. Therefore, the above findings will be an initial step for the regulatory authorities of Bangladesh to implement regulations and guidelines for pesticide usage.

Enrichment, sources, and distributions of toxic elements in the farming land's topsoil near a heavily industrialized area of central Bangladesh, and associated risks assessment.

Toxic element accumulation in the surrounding soils of the advanced industry- and agriculture-oriented areas may lead to severe environmental degradation and harmful impact on inhabitants. This work examined the concentration of some concerned toxic elements (Cr, Pb, Cd, Cu, As, and Ni) in the representative topsoil from 10 industrially contaminated sites in central Bangladesh (Narayanganj district) using an Inductively Coupled Plasma Mass Spectrometer concerning the probable ecological and human health risks. The mean concentrations (mg/kg) of the elements were found in the order of Ni (58.1 ± 11.8) > Pb (34.1 ± 14.3) > Cr (32.1 ± 6.77) > Cu (14.5 ± 3.30) > Cd (2.74 ± 1.08) > As (1.49 ± 0.43). The findings pointed out that diversified manmade events enhanced the intensities of elemental contamination through the studied sites. Source analysis showed that Cr, Pb, As, and Cd may originate from industrial wastewater and agricultural activities, whereas Cu and Ni came from natural sources. The geo-accumulation index level for Cd (1.70-3.39) was determined as grade 3 (moderately to strongly polluted), the enrichment factor score for Cd (13.9) fell in the very severe enhanced category (cluster 5), and the highest contamination factor value was found for Cd (15.7). The contamination degree values for all the tested elements signify a moderate to severe contamination grade; conversely, pollution load index levels depicted the nonexistence of elemental pollution. The assessment revealed serious Cd pollution in agricultural soils and moderate to significant potential ecological risk for the rest of the examined toxic elements. Furthermore, hazard index values exceeded the safe exposure levels, indicating that there was potential non-carcinogenic risk in the soils for children and adults. Ingestion exposure had much higher carcinogenic risk values than inhalation and cutaneous exposure, and children are exposed to considerable carcinogenic hazards. Therefore, it is suggested that the harmful practices that expose this farming soil to contaminants should be stopped immediately and effective environment-friendly techniques of waste management and effluent treatment should be employed in the study area.

Comparison of antigenicity between recently isolated bovine rotaviruses A and vaccine strains by cross-neutralizing antibody tests and their significance for immunization.

Three bovine rotaviruses A (RVAs) isolated from a cattle farm in Japan were serotyped by serum neutralization assay, as compared with the RVA strains contained in a vaccine used on the same farm. Antisera were prepared against the three isolates and the vaccine strains of bovine RVA. The results of cross-neutralization tests revealed that the RVA isolates from this farm differed somewhat in serotype. Collected plasma from calves for 6 weeks after colostrum ingestion showed that maternal antibodies acquired against all isolates gradually decreased, but antibodies toward one isolate increased by 6 weeks after the mentioned decreasing. These results suggest that rotavirus vaccines administered to cows should include all serotypes commonly found in calves with diarrhea.

Pollution characteristics and risk assessment of potentially toxic elements of fine street dust during COVID-19 lockdown in Bangladesh.

Due to the COVID-19 pandemic, Bangladesh government took the measure like partial lockdown (PL) and complete lockdown (CL) to curb the spread. These measures gave a chance for environmental restoration. In this study, street dust samples were collected during PL and CL from four main urban land use categories in Dhaka city, such as industrial area (IA), commercial area (CA), public facilities area (PFA), and residential area (RA). Ten potentially toxic elements (Cr, Mn, Zn, Fe, Pb, Cu, Co, Ni, As, and Cd) in fine street dust particles (diameter < 20 µm) were determined following aqua-regia digestion and measured by inductively coupled plasma mass spectrometry (ICP-MS) to evaluate distribution, pollution sources, and potential risks to ecological systems and human health. Results showed that during PL, the concentrations of toxic elements in the dust were higher than that of CL. Cd and Fe were lowest and highest in concentration with 1.56 to 41,970 µg/g and 0.82 to 39,330 µg/g in partial and complete lockdown period respectively. All toxic elements were detected at high levels above background values where Fe with the highest and Cd with lowest concentrations, respectively. By land use, the levels of toxic elements pollution followed IA > PFA > RA > CA. Correlation analysis (CA), principal component analysis (PCA), and hierarchal cluster analysis (HCA) revealed that the sources of these analyzed toxic elements were mainly from anthropogenic which are related to industrial and vehicular or traffic emissions. Enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI) also suggested that the dust was more polluted during PL. Exposure of toxic elements to human was mainly via skin contact followed by ingestion and inhalation. Hazard quotient (HQ) values were < 1 except for Mn through dermal contact at all sites during partial and complete lockdown, similar to hazard index (HI), while Cr further showed high non-carcinogenic risks to children. Generally, children HI values were about 5-6 times higher than those of adults, suggesting a greater vulnerability of children to the health concerns caused by toxic elements in street dust. Carcinogenic risk (CR) values via ingestion pathway indicated all elements (except Pb) had significant health effect, while CR value by inhalation results showed no significant health effect. Cumulative carcinogenic risk (CCR) value had significant health effect except Pb in all land use categories. CCR values decreased during CL and reached at acceptable limit for most of the cases. This research provides a message to the local governments and environmental authorities to have a complete assessment of toxic elements in the street dust of Dhaka megacity in order to assuring public health safety and ecological sustainability.

Hydrochemical appraisal of surface water from a subtropical urban river in southwestern Bangladesh using indices, GIS, and multivariate statistical analysis.

The Gorai River is a significant river in Bangladesh's southwestern region, where residents make great use of the water despite a lack of adequate and reliable information concerning water quality and pollution levels. Thus, the goal of this research was to examine the spatio-temporal variations in water quality and determine whether it was suitable for drinking, agriculture, industrial, or livestock purposes, as well as the influencing factors and potential sources of water pollution. Surface water samples were collected in wet and dry seasons from ten sampling sites, and twenty water quality parameters were evaluated. The results showed that some studied water quality parameters, e.g., temperature, electrical conductivity, alkalinity, and nitrate, exceeded the maximum allowable limit. Water quality index values exhibited that the water quality of all sampling sites was found to be poor to very poor during the wet season, while only St-4 and St-5 were found to be poor and the rest of the investigated sites were good category during the dry season. Based on sodium adsorption ratio, soluble sodium percentage, residual sodium carbonate, residual sodium bicarbonate, and permeability index values, it was depicted that river water was suitable for irrigation purposes, but when compared to Kelly's ratio (KR) and magnesium hazard ratio values, river water was found to be unfit for irrigation. Moreover, potential salinity (PS) and sodium-to-calcium activity ratio (SCAR) values allow the water as moderately suitable for use in irrigation purposes. Langelier saturation index (LSI) and aggressive index (AI) values revealed that the river water was under saturated to supersaturated and moderate to non-aggressive in nature. However, Ryznar stability index (RSI), Puckorius scaling index (PSI), and Larson-Skold index (LS) values describe whether the water was high or severely corrosive, signifying its inappropriateness for industrial consumption. Principal component analysis (PCA) analysis depicted that the fluctuations in water quality are mostly related to point and non-point contaminations, such as urban and industrial effluent discharged and agricultural runoff of fertilizers. Cluster analysis (CA) revealed relative geographical and seasonal changes in water quality, showing the impact of hydrological changes and contamination.

Isolation, molecular characterization, and disinfectants susceptibility of swine-carried mammalian orthoreoviruses in Japan in 2020-2022.

Biosecurity enhancement contributes to the reduction of various microbial pathogens. Mammalian orthoreoviruses (MRVs) which are increasingly recognized as potentially serious problems on swine industry were used as indicators of biosecurity enhancement on two pig farms. Twelve MRVs were detected and isolated from fecal specimens of healthy pigs collected from one of the two farms in Japan. By sequencing based on the partial S1 gene, MRV isolates were classified as MRV1 and MRV2. Additionally, the virucidal activities of disinfectants toward the isolated MRV1 were evaluated using quaternary ammonium compound (QAC) diluted 500 times with water (QAC-500), 0.17% food additive glade calcium hydroxide (FdCa(OH)2) solution, QAC diluted with 0.17% FdCa(OH)2 solution (Mix-500), sodium hypochlorite at 100 or 1,000 parts per million (ppm) of total chlorine (NaClO-100 or NaClO-1000, respectively). To efficiently inactivate MRV1 (≥3 log10 reductions), 0.17% FdCa(OH)2, Mix-500 and NaClO-1000 required 5 min, whereas it took 30 min for QAC-500. The number of MRV detections has decreased over time, after using Mix-500 for disinfection on the positive farm. These results suggest that different serotypes of MRVs are circulating among pigs, and that the occurrence of MRVs in the farms decreased consequent to more effective disinfection.

Arsenic in the foodstuffs: potential health appraisals in a developing country, Bangladesh.

The presence of highly poisonous arsenic (As) elements in food concerns humans and animals. In Bangladesh, arsenic-contaminated groundwater is frequently utilized for agricultural irrigation. This is a significant source of arsenic pollution in the human food chain. For the first time, we investigated the presence of total arsenic in various foodstuffs obtained from 30 distinct agricultural eco-zones of Bangladesh to understand human exposure to arsenic through the food chain in Bangladesh. The greatest and lowest As concentrations were reported in fish among the examined dietary items (0.55 mg/kg, fw) and fruit (0.0068 mg/kg, fw), respectively. The results show that arsenic consumption from daily diet and food with drinking water was estimated to be 0.0352 mg/day for rural residents and 0.2002 mg/day for urban residents, respectively. The highest target hazard quotients (THQ) of arsenic in the fish samples surpassed the allowable limit (> 1), proving that fish are the primary dietary items influencing the possible danger to health. However, the target cancer risk (TR) from nutritional arsenic consumption was likewise higher than tolerable. A value of 10-4 indicates that Bangladeshi people are continuously exposed to arsenic, which has carcinogenic and non-carcinogenic dangers. Overall, our results highlight that people in Bangladesh are exposed to hazardous levels of arsenic throughout the food chain, which should be addressed to ensure the country's food safety.

Sources and management of marine litter pollution along the Bay of Bengal coast of Bangladesh.

Marine debris is often detected everywhere in the oceans after it enters the marine ecosystems from various sources. Marine litter pollution is a major threat to the marine ecosystem in Bangladesh. A preliminary study was conducted to identify the sources of marine litter (plastics, foamed plastic, clothes, glass, ceramic, metals, paper, and cardboard) along the Bay of Bengal coast. From the observations, the range of abundance of the collected marine litter was 0.14-0.58 items/m2. From the ten sampling sites, the highest amount of marine litter was observed for aluminium cans (3500), followed by plastic bottles (3200). The spatial distribution pattern indicated that all the study areas had beach litter of all types of materials. The present investigation showed that plastics were the dominating pollutants in the marine ecosystem in Bangladesh. The clean-coast index (CCI) value indicated that the Cox's Bazar coast was clean to dirty class. The abundance, distribution, and pollution of marine litter along the coastal belts pose a potential threat to the entire ecosystem. This study will help come up with ways to manage and get rid of marine litter along the coast in an effective way.

How can humanitarian services provision during mass displacement better support health systems? An exploratory qualitative study of humanitarian service provider perspectives in Cox's Bazar, Bangladesh.

Health services provision in mass displacement settings is a humanitarian imperative and essential to promoting international and regional security. Internationally displaced populations experience a range of issues pre-, peri-, post-displacement and residing in host countries that affect their health and well-being. This study examined links between humanitarian and government health services provision for forcibly displaced Myanmar nationals (FDMN) in Cox's Bazar to consider how improved knowledge sharing and collaboration might better support health systems during mass displacement. We conducted a qualitative descriptive study, interviewing 25 humanitarian service providers in-person in Bangladesh in early 2021 and analysing data thematically. We found that government restricted what essential services humanitarian health actors could provide and FDMN had to undergo stringent screening and referral to receive tertiary healthcare. Concurrently, the government health system was challenged by accessibility, affordability and availability of medicines, equipment, and trained staff. Humanitarian health service providers augmented government responses by working with community groups, recruiting and training Rohingya volunteers, and involving religious leaders. Findings suggest that easing barriers to a fuller range of health services, allowing access to digital devices, and hiring FDMN to support their communities would improve health system responsiveness to the legitimate needs of FDMN displaced around Cox's Bazar. It is imperative to amplify and listen to the voices of FDMN and collaborate in addressing structural and social barriers constraining their access to effective health services, both to increase trust in and responsiveness of the health system.

A Fast Adsorption of Azithromycin on Waste-Product-Derived Graphene Oxide Induced by H-Bonding and Electrostatic Interactions.

Graphene oxide (GO) was prepared from the graphite electrode of waste dry cells, and the application of the prepared GO as a potential adsorbent for rapid and effective removal of an antibiotic, azithromycin (AZM), has been investigated. The synthesis process of GO is very simple, cost-effective, and eco-friendly. As-prepared GO is characterized by field-emission scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller sorptometry, and zeta potential analysis. The obtained GO has been employed for removal of the widely used AZM antibiotic from an aqueous solution. The quantitative analysis of AZM before and after adsorption has been carried out by liquid chromatography tandem mass spectrometry. The adsorption of AZM by GO was performed in a batch of experiments where the effects of adsorbent (GO) dose, solution pH, temperature, and contact time were investigated. Under optimum conditions (pH = 7.0, contact time = 15 min, and adsorbent dose = 0.25 g/L), 98.8% AZM was removed from the aqueous solution. The rapid and effective removal of AZM was significantly controlled by the electrostatic attractions and hydrogen bonding on the surface of GO. Adsorption isotherms of AZM onto GO were fitted well with the Freundlich isotherm model, while the kinetic data were fitted perfectly with the pseudo-second order. Therefore, the simple, cost-effective, and eco-friendly synthesis of GO from waste material could be applicable to fabricate an effective and promising low-cost adsorbent for removal of AZM from aqueous media.