Removal of arsenic from jarosite waste using hydrometallurgical treatment.

The jarosite waste used during this study consists of minute amount of arsenic that has a potential to be leached into environment when kept in open area. This study tried to recover arsenic from jarosite waste using hydrometallurgical treatment. The comprehensive characterization of jarosite samples was performed using various analytical techniques, including X-ray diffraction (XRD), Fourier transform Infrared (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), and it was characterized as natrojarosite. For optimal removal of arsenic, the response surface methodology (RSM) was applied with the key factors, including dosage (A), time (B), temperature (C), and acid concentration (D) on the recovery of arsenic. The results indicated that the dosage (A) and acid concentration (D) demonstrated significant positive effects on arsenic recovery. As expected, the higher dosage and acid concentration was associated with increased recovery percentages for the arsenic from jarosite. Whereas time (B) and temperature (C) did not exhibit statistically significant recovery of arsenic within the specified experimental range. The contour plots showed the optimal operating conditions for the highest recovery percentage was approximately 52.61% when 2.5 g of jarosite was treated with 10 mol/L acid for 150 min at operating temperature of 80°. Although our study showed very moderate recovery of arsenic, it is first report where arsenic has been removed from jarosite waste. Readjustment of range of operating parameters would provide more insight into the further optimization of the yield.

Multi-locus sequence analysis reveals phylogenetically segregated Entamoeba histolytica population.

Amoebiasis, caused by the enteric parasite, Entamoeba histolytica, is one of the major food- and water-borne parasitic diseases in developing countries with improper sanitation and poor hygiene. Infection with E. histolytica has diverse disease outcomes, which are determined by the genetic diversity of the infecting strains. Comparative genetic analysis of infecting E. histolytica strains associated with differential disease outcomes from different geographical regions of the world is important to identify the specific genetic patterns of the pathogen that trigger certain disease outcomes of Amoebiasis. The strategy is able to elucidate the genealogical relation and population structure of infecting E. histolytica strains from different geographical regions. In the present study, we have performed a comparative genetic analysis of circulating E. histolytica strains identified from different parts of the world, including our study region, based on five tRNA-linked short tandem repeat (STR) loci (i.e., D-A, NK2, R-R, STGA-D and A-L) and evaluated their potential associations with differential disease outcomes of Amoebiasis. A number of regional-specific, emerging haplotypes of E. histolytica, significantly associated with specific disease outcomes have been identified. Haplotypes, which have a significant positive association with asymptomatic and amoebic liver abscess outcomes, showed a significant negative association with diarrheal outcome, or vice versa. Comparative multi-locus analysis revealed that E. histolytica isolates from our study region are phylogenetically segregated from the isolates of other geographical regions. This study provides a crucial overview of the population structure and emerging pattern of the enteric parasite, E. histolytica.

Prevalence of pharmaceuticals and personal care products, microplastics and co-infecting microbes in the post-COVID-19 era and its implications on antimicrobial resistance and potential endocrine disruptive effects.

The COVID-19 (coronavirus disease 2019) pandemic's steady condition coupled with predominance of emerging contaminants in the environment and its synergistic implications in recent times has stoked interest in combating medical emergencies in this dynamic environment. In this context, high concentrations of pharmaceutical and personal care products (PPCPs), microplastics (MPs), antimicrobial resistance (AMR), and soaring coinfecting microbes, tied with potential endocrine disruptive (ED) are critical environmental concerns that requires a detailed documentation and analysis. During the pandemic, the identification, enumeration, and assessment of potential hazards of PPCPs and MPs and (used as anti-COVID-19 agents/applications) in aquatic habitats have been attempted globally. Albeit receding threats in the magnitude of COVID-19 infections, both these pollutants have still posed serious consequences to aquatic ecosystems and the very health and hygiene of the population in the vicinity. The surge in the contaminants post-COVID also renders them to be potent vectors to harbor and amplify AMR. Pertinently, the present work attempts to critically review such instances to understand the underlying mechanism, interactions swaying the current health of our environment during this post-COVID-19 era. During this juncture, although prevention of diseases, patient care, and self-hygiene have taken precedence, nevertheless antimicrobial stewardship (AMS) efforts have been overlooked. Unnecessary usage of PPCPs and plastics during the pandemic has resulted in increased emerging contaminants (i.e., active pharmaceutical ingredients and MPs) in various environmental matrices. It was also noticed that among COVID-19 patients, while the bacterial co-infection prevalence was 0.2-51%, the fungi, viral, protozoan and helminth were 0.3-49, 1-22, 2-15, 0.4-15% respectively, rendering them resistant to residual PPCPs. There are inevitable chances of ED effects from PPCPs and MPs applied previously, that could pose far-reaching health concerns. Furthermore, clinical and other experimental evidence for many newer compounds is very scarce and demands further research. Pro-active measures targeting effective waste management, evolved environmental policies aiding strict regulatory measures, and scientific research would be crucial in minimizing the impact and creating better preparedness towards such events among the masses fostering sustainability.

Repurposing the single-used-plastic for development of hydrophobic aerogels for remediation of oil spill and organic solvents.

Currently, around 400 million tonnes of synthetic polymers are being dumped as waste annually and by this rate by 2050 the ocean would contain more such waste compared to the total weight of fish. As recycling could solve part of this problem, recently such waste is being reused for various purposes like composite preparation, oil production and various other use such as production of foams, sponges, and aerogels. However, there is a relatively limited literature available on the utilization of polyethylene polymer (like LDPE). The study presented in this article indicated that LDPE-based polymers could be reused (after modification) for preparation of hydrophobic, lightweight, and porous aerogels that have oil-spills and organic solvent adsorption capacity. The aerogels showed contact angle of 121.9o, bulk density below 0.25 g/cm3, and were found to be semi-crystalline. The aerogels showed oil and solvent adsorption more than that for their untreated counterparts. Also, the aerogels were found to be recycled for more than five cycles with very minimum loss of efficacy. This area of producing oil sorbents from single used plastic wastes is still very open for further research and seems to be a promising route for both waste reduction, and the synthesis of value-added products. This could be one of the most sustainable approaches for efficient single-used plastic wase management and environment clean-up.

Recovery of residual metals from jarosite waste using chemical and biochemical processes to achieve sustainability: A state-of-the-art review.

Jarosite is a residue that is generated as a by-product during zinc extraction, and it consists of various types of heavy metal (loid)s such as arsenic, cadmium, chromium, iron, lead, mercury and silver. Due to the huge jarosite turn-over rate, and less efficient and expensive residual metal extraction processes, the zinc-producing industries dispose this waste in landfills. However, the leachate generated from such landfills contains a high concentration of heavy metal (loid)s that could contaminate the nearby water resources and cause environmental concern and human health risk. Various thermo-chemical and biological processes have been developed for the recovery of heavy metals from such waste. In this review, we have discussed all those pyrometallurgical, hydrometallurgical, and biological. Those studies were critically reviewed and compared on the basis of their techno-economic differences. The review indicated that these processes have their own benefits and drawbacks such as overall yield, economic and technical constraints, and the need for more than one process to mobilize multiple metal ions from jarosite. Also, in this review, the residual metal extraction processes from jarosite waste have been linked with the relevant UN Sustainable Development Goals (SDGs), which can be useful for a better approach to sustainable development.

Polymeric biomaterials-based tissue engineering for wound healing: a systemic review.

Background: Biomaterials are vital products used in clinical sectors as alternatives to several biological macromolecules for tissue engineering techniques owing to their numerous beneficial properties, including wound healing. The healing pattern generally depends upon the type of wounds, and restoration of the skin on damaged areas is greatly dependent on the depth and severity of the injury. The rate of wound healing relies on the type of biomaterials being incorporated for the fabrication of skin substitutes and their stability in in vivo conditions. In this review, a systematic literature search was performed on several databases to identify the most frequently used biomaterials for the development of successful wound healing agents against skin damage, along with their mechanisms of action. Method: The relevant research articles of the last 5 years were identified, analysed and reviewed in this paper. The meta-analysis was carried out using PRISMA and the search was conducted in major scientific databases. The research of the most recent 5 years, from 2017-2021 was taken into consideration. The collected research papers were inspected thoroughly for further analysis. Recent advances in the utilization of natural and synthetic biomaterials (alone/in combination) to speed up the regeneration rate of injured cells in skin wounds were summarised. Finally, 23 papers were critically reviewed and discussed. Results: In total, 2022 scholarly articles were retrieved from databases utilizing the aforementioned input methods. After eliminating duplicates and articles published before 2017, ~520 articles remained that were relevant to the topic at hand (biomaterials for wound healing) and could be evaluated for quality. Following different procedures, 23 publications were selected as best fitting for data extraction. Preferred Reporting Items for Systematic Reviews and Meta-Analyses for this review illustrates the selection criteria, such as exclusion and inclusion parameters. The 23 recent publications pointed to the use of both natural and synthetic polymers in wound healing applications. Information related to wound type and the mechanism of action has also been reviewed carefully. The selected publication showed that composites of natural and synthetic polymers were used extensively for both surgical and burn wounds. Extensive research revealed the effects of polymer-based biomaterials in wound healing and their recent advancement. Conclusions: The effects of biomaterials in wound healing are critically examined in this review. Different biomaterials have been tried to speed up the healing process, however, their success varies with the severity of the wound. However, some of the biomaterials raise questions when applied on a wide scale because of their scarcity, high transportation costs and processing challenges. Therefore, even if a biomaterial has good wound healing qualities, it may be technically unsuitable for use in actual medical scenarios. All of these restrictions have been examined closely in this review.

Current synthesis and characterization techniques for clay-based polymer nano-composites and its biomedical applications: A review.

Clays and its composites have received considerable attention recently due to their low cost, wide availability and low environmental impact. The development of various preparation processes and applications of innovative polymer-nanoclay composites has been aided by recent breakthroughs in material technologies. Novel polymer-nanoclay composites with better qualities have been effectively adopted in a variety of fields, including aerospace, car, construction, petroleum, biomedical, and wastewater treatment, owing to innovative production processes. Due to their superior qualities, such as increased density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic capabilities, these composites are acknowledged as potential advanced materials. Hence the present paper reviews the advances in synthesis and preparation of clay-polymer nanocomposites. In addition, this study also focuses on the various techniques used for clay-polymer nanocomposites characterization e.g. scanning electron microscope (SEM), transmission electron microscope (TEM), thermo-gravimetric analysis (TGA) and differential colorimetric analysis (DSC), x-ray diffraction (XRD) analysis, Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopic (FTIR) characterization. These advanced physico-mechanical and chemical characterization techniques would be effective in understanding the most appropriate application of clay polymer nanocomposites. In addition, the application of clay polymer nanocomposites in biomedical sector is also discussed in brief.

Critical review on negative emerging contaminant removal efficiency of wastewater treatment systems: Concept, consistency and consequences.

Emerging contaminants (ECs) are not completely removed by wastewater treatment owing to their capabilities of making complexes, toxic derivatives, byproduct formation, and dynamic partitioning. Negative contaminant removal i.e., higher concentrations (up to 5731%) of these ECs in the effluent with respect to the influent sampled on the same occasions, is globally prevalent in almost all types of treatment systems. Conventional WWTPs showed the highest negative removal (NR) for Carbamazepine, and Carbadox. Conjugation-deconjugation, types of WWTPs, transformations, leaching, operational parameters, sampling schemes, and nature of substance governs the NR efficiencies. Among the various categories of micropollutants, pesticides and beta-blockers are reported to exhibit the maximum percentage of NR, posing threat to human and the environment. With > 200% of NR for beta-blockers, low blood-pressure related symptoms may likely to get more prevalent in the near future. Study red-flags this phenomenon of negative removal that needs urgent attention.

Game of transmissions (GoT) of SARS-CoV-2: Second wave of COVID-19 is here in India.

Corona virus disease (COVID-19) pandemic had taken the humankind by surprise, yet the world laid out a historical battle against all the odds. Laboratory findings have never been so rapidly made available to common public and authorities. Experimental data on COVID-19 from across the globe was directly made accessible worldwide. The second wave of the pandemic in India caused unprecedented havoc and it can be stated that all the knowledge of the game of transmission of COVID-19 acquired and shared was not played with right precision and preparations. Rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the second phase made us rethink if the choice of information given to the common people pertaining to the selective transmission restriction pathways with pressing concern on lethality were inadequate. Most of the governmental and non-governmental organizations (NGOs) including the World Health Organization (WHO) recommended droplet-based and airborne transmission restrictions as the major steps to control rapid spread of the virus. While, no caution was advised for other plausible pathways like sewage, wastewater-based and non-ventilated indoor air-based transmissions, which are still unknown or not well investigated, and are equally dangerous. The main focus of this article is to analyse the past development about SARS-CoV-2 transmission pathway related recommendation(s) provided by WHO and track the trajectory to alert all the concerning stakeholders and policymakers to rethink and to collect adequate scientific data before they recommend or neglect any specific or all the possible transmission pathways to control the spread of infectious agents further.

Facile green synthesis of non-genotoxic, non-hemolytic organometallic silver nanoparticles using extract of crushed, wasted, and spent Humulus lupulus (hops): Characterization, anti-bacterial, and anti-cancer studies.

Since the last few decades, the green synthesis of metal nanoparticles was one of the most thrust areas due to its widespread application. The study proposed using wasted and unusable Humulus lupulus (Hops) extract to synthesize silver nanoparticles for biomedical application. The environment around us gives us many scopes to use the waste from environmental sources and turn it into something valuable. The spent Hops extract was used to synthesize silver nanoparticles (AgNP@HOPs), and the synthesized product exhibited an excellent therapeutic effect in terms of anti-bacterial and anti-cancer agents. The synthesis was optimized considering different factors like time and the concentration of AgNO3. The silver nanoparticles were characterized in detail using different characterization techniques XRD, DLS, TEM, BET, XPS, Raman Spectroscopy, SEM, EDAX, AFM, which revealed the uniqueness of the silver nanoparticles. The average hydrodynamic size was found to be 92.42 ± 2.41 with a low polydispersity index. The presence of Ag-C and Ag-O bonds in the AgNP@HOPs indicated that it is composed of organo-silver and silver oxides. The nanoparticles were found to be spherical with an average size of 17.40 nm. The AgNPs were lethal to both E. coli and S. aureus with a MIC-50 of 201.881 µg/mL and 213.189 µg/mL, respectively. The AgNP@HOPs also exhibited an anti-cancer effect with an IC-50 of 147.175. The AgNP@HOPs exhibited less cytotoxicity and genotoxicity against normal cells and exhibited superior haemocompatibility (major criteria for drug selection). There are indeed various reports on the synthesis of silver nanoparticles, but this study proposes a green method for producing non-genotoxic, non-hemolytic organometallic silver nanoparticles using waste material with considerable therapeutic index from the environmental source with potential application in the medical industry. This work could be taken forward for in-vivo studies and for pre clinical studies.

Emerging technologies for sustainable production of biohydrogen production from microalgae: A state-of-the-art review of upstream and downstream processes.

Biohydrogen (BioH2) is considered as one of the most environmentally friendly fuels and a strong candidate to meet the future demand for a sustainable source of energy. Presently, the production of BioH2 from photosynthetic organisms has raised a lot of hopes in the fuel industry. Moreover, microalgal-based BioH2 synthesis not only helps to combat current global warming by capturing greenhouse gases but also plays a key role in wastewater treatment. Hence, this manuscript provides a state-of-the-art review of the upstream and downstream BioH2 production processes. Different metabolic routes such as direct and indirect photolysis, dark fermentation, photofermentation, and microbial electrolysis are covered in detail. Upstream processes (e.g. growth techniques, growth media) also have a great impact on BioH2 productivity and economics, which is also explored. Technical and scientific obstacles of microalgae BioH2 systems are finally addressed, allowing the technology to become more innovative and commercial.

Separation of pollutants from aqueous solution using nanoclay and its nanocomposites: A review.

Wastewater is always composed of different pollutants, most of which are toxic to the living being. It is very tough to separate all those diverse groups of contaminants using a single process or single material. Rather a sustainable and environment friendly processes should be adapted to restrict the secondary pollution generation. Nanoclay and its nanocomposites are one of the most used adsorbents that have been modified and used for the separation of almost all types of pollutants, including dyes, heavy metals, fluoride, nitrate, ammonia, emerging pollutants and bacteria. They are relatively inexpensive, easy to exploit and relatively maintenance-free. Thus, recent research bloomed for developing suitable adsorbents, including clay nanocomposites. The advantages and drawbacks of all the clay nanocomposites-based processes have been discussed critically in this article. Nano-clays or other nanoparticles incorporated synthetic and natural polymers-based clay nanocomposites were synthesized, and it was found that they can remove dyes in the range between 48 mg/g and 1994 mg/g. Similarly, they separate a diverse group of heavy metal ions, including As, Cu, Co, Pd, Zn, Cr, Ni, Cd, and Hg, in the range of 0.073-1667 mg/g. The clay nanocomposites also showed fluoride removal efficacy in the range of 0.134-23 mg/g. They are also useful for the separation of emerging pollutants like pesticides, pharmaceuticals, personal care products, trace elements, and particulate matters in the range of 0.1-651 mg/g the clay nanocomposites showed considerable nitrate, ammonia and bacteria removal efficacy too. Though it seems promising, more investigations with real wastewater and pilot-scale studies are recommended to explore large-scale wastewater treatment capabilities.

Fixed bed column study for water defluoridation using neem oil-phenolic resin treated plant bio-sorbent.

Fluoride has both detrimental and beneficial effects on living beings depending on the concentration and consumption periods. The study presented in this article investigated the feasibility of using neem oil phenolic resin treated lignocellulosic bio-sorbents for fluoride removal from water through fixed bed column study. Results indicated that treated bio-sorbents could remove fluoride both from synthetic and groundwater with variable bed depth, flow rate, fluoride concentration and column diameter. Data obtained from this study indicated that columns with the thickest bed, lowest flow rate, and fluoride concentration showed best column performance. Bio-sorbents used in this study are regenerable and reusable for more than five cycles. The initial materials cost needed to remove one gram of fluoride also found to be lower than the available alternatives. This makes the process more promising candidate to be used for fluoride removal. In addition, the process is also technically advantageous over the available alternatives.

Enhanced biodegradation resistance of biomodified jute fibers.

A bio-catalyzed process has been developed for treating jute fibers to enhance their tensile strength and resistance against biodegradation. Lipolytic bacteria were used in the process to transesterify jute fibers by replacing hydrophilic hydroxyl groups within cellulose chains with hydrophobic fatty acyl chains. Transesterification of some of the hydroxyl groups within the fiber was confirmed with FTIR, UV-vis spectroscopy, (13)C solid state NMR, gas chromatography and analytical determination of ester content. Biomodified fibers exhibited remarkably smaller affinity to water and moisture and retained 62% of their initial tensile strengths after being exposed to a composting environment over 21 days. The corresponding figure for untreated fibers was only 30%. Efficacy of the process reported herein in terms of tensile strength and biodegradation resistance enhancement of fibers achieved after treatment appears to be comparable with similar chemical processes and better than the enzyme-catalyzed alternatives.

Enhancement of tensile strength of lignocellulosic jute fibers by alkali-steam treatment.

The physico-chemical properties of jute fibers treated with alkali (NaOH) solution have been investigated in this study. The treatments were applied under ambient and elevated temperatures and high pressure steaming conditions. To the knowledge of these authors the influence of alkali-steam treatment on the uniaxial tensile strength of natural ligno-cellulosic fibers, such as jute, has not been investigated earlier. The results from this investigation indicate that a 30 min dipping of the fibers in 0.5% alkali solution followed by 30 min alkali-steam treatment leads to an increase in the tensile strength of up to 65%. The increase appears to be due to fiber separation and removal of non-cellulosic materials, which, in turn, resulted in an increased crystallinity.