Optimization of Polyacrylic Acid Coating on Graphene Oxide-Functionalized Reverse-Osmosis Membrane Using UV Radiation through Response Surface Methodology

Reverse osmosis (RO) is affected by multiple types of fouling such as biofouling, scaling, and organic fouling. Therefore, a multi-functional membrane capable of reducing more than one type of fouling is a need of the hour. The polyacrylic acid and graphene oxide (PAA-GO) nanocomposite functionalization of the RO membrane has shown its effectiveness against both mineral scaling and biofouling. In this research, the polyacrylic acid concentration and irradiation times were optimized for the PAA-GO-coated RO membrane using the response surface methodology (RSM) approach. The effect of these parameters on pure water permeability and salt rejection was investigated. The models were developed through the design of the experiment (DoE), which were further validated through the analysis of variance (ANOVA). The optimum conditions were found to be: 11.41 mg·L−1 (acrylic acid concentration) and 28.08 min (UV activation times) with the predicted results of 2.12 LMH·bar−1 and 98.5% NaCl rejection. The optimized membrane was prepared as per the model conditions, which showed an increase in both pure water permeability and salt rejection as compared to the control. The improvement in membrane surface smoothness and hydrophilicity for the optimized membrane also helped to inhibit mineral scaling by 98%.This publication was made possible by NPRP13S-0207-200289 from the Qatar National Research Fund (a member of the Qatar Foundation). The findings achieved herein are solely the responsibility of the author[s].Scopu

Phytoremediation: Halophytes as Promising Heavy Metal Hyperaccumulators

The continued accumulation of trace and heavy metals in the environment presents a significant danger to biota health, including humans, which is undoubtedly undermining global environmental sustainability initiatives. Consequently, the need for efficient remediation technologies becomes imperative. Phytoremediation is one of the most viable options in this regard. Hundreds of plants in laboratory experiments demonstrate the potential to remediate varying concentrations of heavy metals; however, the remediation capacity of most of these plants proved unsatisfactory under field conditions. The identification and selection of plants with higher metal uptake capacity or hyperaccumulators are one of the limitations of this technology. Additionally, the mechanism of heavy metal uptake by plants remains to be sufficiently documented. The halophyte plants are famous for their adaptation to harsh environmental conditions, and hence could be the most suitable candidates for heavy metal hyperaccumulation. The state of Qatar in the Gulf region encompasses rich resources of halophytes that have the potential for future investment toward human and environmental health. This chapter, therefore, gives an overview of phytoremediation, with emphasis on halophytes as suitable heavy metal hyperaccumulators for improved remediation of heavy metal–contaminated areas

DPSIR framework and sustainable approaches of brine management from seawater desalination plants in Qatar

Brine released from desalination plants is extremely high in salinity and contains various chemicals, which are harmful to the ecosystem. The disposal of brine has raised great concerns for the desalination industry around the world due to its detrimental impact on fauna and flora. This review complies with various zero liquid discharge technologies that have been proposed for successful brine disposal which aims to minimize the impact of brine discharge. Moreover, it highlights some of the detrimental impacts of brine discharge on marine fauna and Flora. It also discusses both thermal and membrane technologies for recovering freshwater, energy, and minerals from waste brine, in addition to the recent advances in a solar pond, membrane distillation, pressure retarded osmosis, etc. In Driver-Pressure-State-Impact-Response (DPSIR) framework was used in this review to analyze the water resource system in Qatar. This review also facilitates and provides a comprehensive approach in minimizing the potential impact of brine discharge which can be practiced and applied in countries where desalination plants are set up. This promotes cleaner production, sustainability, and recycling of waste that will help protect and preserve the country's natural water resources

Development of a novel tailored ion-imprinted polymer for recovery of lithium and strontium from reverse osmosis concentrated brine

This study aims to prepare ion-imprinted polymer (IIP) with the benefit of a metal-based sorbent, which is fabricated to selectively adsorb lithium (Li+) from aqueous solutions, and in an attempt to remove strontium (Sr2+). The adsorption processes were carried out at different pH values, initial concentrations, and temperatures, to optimize the experimental conditions, with the use of response surface methodology (RSM). The seawater reverse osmosis (SWRO) brine was physically and chemically characterized, and the physicochemical characterization of the prepared IIP before and after adsorption was also performed using different spectroscopic methods. The adsorption capacity for Li+ and Sr2+ from SWRO brine was evaluated, and the reusability of IIP was investigated using adsorption–desorption cycles. The results showed that the IIP was efficient to remove Li+ but not Sr2+, and it follows Freundlich adsorption isotherms models. The analysis revealed a significant concentration of minerals in the brine sample It also revealed a low concentration of trace metals, like Ba (0.16 mg/L), Zn (0.845 mg/L), Fe (1.31 mg/L), Cu (1.165 mg/L), Pb (1.505 mg/L), and V (3.88 mg/L), except Li and Sr which shows a higher concentration of 43.32 mg/L and 16.93 mg/L respectively. pH 10 was selected to be the optimum pH for the adsorption isotherm experiments, as it was the highest efficient pH to adsorb Li+ and Sr2+. The thermodynamics study revealed that the adsorption of Li+ on the IIP favored exothermic conditions. It was noticed that the maximum adsorption capacity (Qm) was increased as the temperature rise from 714.3 mg/g at 25 °C to 2500 mg/g at 45 °C. The Li+ desorption results show that 94.03% − 94.71% of the ions were recovered, while the Sr2+ desorption results show that 96.35% − 96.56% of the ions were recovered. The efficiency of IIP to adsorb lithium and strontium from brine shows that the adsorption removal% of Li+ was between 84.21% and 84.68%, while the adsorption removal% of Sr2+ was between 3.83% and 10%. The cost analysis for IIP preparation was 2 USD/g.This work was made possible by Qatar University collaborative internal grant [QUCG-CAS-20/21-2]. The findings achieved herein are solely the responsibility of the author[s]. The ICP-MS, SEM, and TEM were accomplished in the Central Laboratories Unit, Qatar University. XRD was accomplished in the Center of Advanced Materials, Qatar University. XPS was accomplished in the Gas Processing Center, Qatar University. Open Access funding provided by the Qatar National Library

Investigating the simultaneous removal of hydrocarbons and heavy metals by highly adapted Bacillus and Pseudomonas strains

The status, content and availability of heavy metals and hydrocarbons are highly affected by weathering processes – particularly – in areas characterized by harsh conditions. Their concomitant removal by highly adapted strains of Bacillus and Pseudomonas to weathered oil components was investigated. Indeed, weathered soil collected from Dukhan dumpsite was shown to contain 14 heavy metals with concentrations exceeding the US-EPA limits. Their distribution in such soil was not affected by the soil organics, which is important for the remediation processes. Most of them were strongly bonded to the iron–manganese oxide and the residual fractions, justifying their bioremediation. This study used 18 adapted bacterial strains isolated from extremely weathered oily soils, including the studied soil, all shown tolerant up to 5 mM and above of heavy metals. 4 Bacillus and 3 Pseudomonas strains exhibited the capability to remove 70%–80% of the heavy metals. Concomitantly, they removed up to 73% of the diesel-range organics. Using the PCA methodology with multivariate (bacterial type and adaptation and heavy metals properties), the efficiency of heavy metals removal was shown not related to the adapted bacteria, but to the heavy metal status. This means that the adaptation of these bacterial strains was at the level of the cells’ structure and/or their exopolymeric substances which immobilize the heavy metals and reduce their toxicity allowing their growth and removing hydrocarbons. It is then, a double-adaptation route, leading to concomitant removal of organics and heavy metals, which is of high importance from the practical point of view

Evaluating the effect of antiscalants on membrane biofouling using FTIR and multivariate analysis

A combination of Fourier-transform infrared (FTIR) spectroscopy, multivariate analysis and conventional microbiological assays were utilized to characterize and differentiate membrane biofouling formed in the presence of antiscalants. Based on the FTIR spectra of biofouled reverse osmosis membranes obtained after incubating with antiscalants and H. aquamarina (as model microorganism), it was found that the biofouling intensity and composition was dependent on the type of antiscalants used. The growth of the bacterium was also highly affected by the type of antiscalants as shown by the colony forming unit (CFU) counts. By combining the techniques of principle component analysis (PCA) and FTIR, it was demonstrated that the biofouling was more intense and composed of proteins, polysaccharides and lipids, when polymer antiscalant was used. By applying PCA-FTIR with CFU counts, faster prediction of the effect of antiscalants on biofouling was made possible. 2019, 2019 Informa UK Limited, trading as Taylor & Francis Group.This publication was made possible by NPRP grant # [9-318-1-064] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. Many thanks to Mr Fathy Atia and Ms Muneera (Central Laboratory Unit?QU) for their efforts in FTIR analysis. Special thanks to Ms Dana A. Da?na and Ms Shazia Bibi for their assistance in the laboratory work.Scopu

Phytoremediation of heavy metals using Qatari flora

Phytoremediation is a natural phenomenon utilizing plants species to reduce or remove organic and inorganic pollutants from contaminated soil, water and sediment sources. Several studies were conducted to demonstrate the phytoremediation potentials of plants species, some of which are also found in Qatar as native or invasive plants. This study investigates the phytoremediation potentials of Zygophyllum qataranse and Salsola imbricata irrigated with a synthetic wastewater typical of oil and gas industry in a mixture of regular and peat moss soil at varying concentrations of heavy metals under greenhouse controlled conditions. Young seedlings of approximately similar weight and height were obtained from Qatar University field and used as starting materials. As an initial observation of tolerance to heavy metal stress, growth parameters such as height and number of branches were monitored and recorded throughout the experimental period of 42 days and a comparison was made for treatment and control plants in both species. Results indicated that the two species S. imbricata and Z. qataranse showed different patterns in response to the different heavy metals stress. Overall growth rate was (0.1; n = 4) for S. imbricata and (0.01; n = 4) for Z. qataranse, one way analysis of variance (ANOVA) confirmed no difference in the effect of the three variable heavy metals concentration used among the two plants, both species also exhibited differences in terms of above the ground biomass, S. imbricata recorded high leaves biomass compared to Z. qataranse, additionally, the leaves of this plant showed no visible signs of stress as opposed to that of Z. qataranse, which appears red after four weeks of irrigation. The root system in S. imbricata, forming typical rhizosphere may have played a key role in the better utilization of the surrounding organic contaminants with the aid of possible activity of associated microbes. Although both thrive in the same habitat naturally, there may actually be differences in their uptake and or tolerance mechanism. Consequently, the analysis and evaluation of measured growth parameters (Height and branches) indicates the potential of both plants as good phytoremediation agents. Further analysis of heavy metal concentration, which is currently ongoing to determine the bio-concentration and translocation factors of the metals between the roots and shoot tissues promise to prove further insight in to this study.qscienc

Health risk assessment of methyl mercury from fish consumption in a sample of adult Qatari residents

Fish constitutes an essential source of high-quality protein and is, at the same time, the source of exposure to many hazardous contaminants, namely mercury and methyl mercury (MeHg). This study aims at assessing the risk that MeHg poses to the health of adult Qatari residents through fish consumption. Data on fish consumption were collected using a self-administered online survey composed of three sections that collected information about the fish-eating patterns of the participants. The fish species that were reported to be consumed by ≥ 3% of the respondents were sampled and analyzed for their total mercury (T-Hg) content levels. MeHg concentrations were derived from T-Hg content levels using a scenario-based approach. Disaggregated fish consumption and contamination data were combined using the deterministic approach to estimate MeHg intakes. The average, 75th, and 95th percentiles of the MeHg intake estimates were determined and compared to the tolerable weekly intake (TWI) set by the European Food Safety Agency (EFSA) (1.3 μg·kg−1·w−1). All fish samples contained T-Hg at levels ˂ 0.3–0.5 µg/g with a mean value of 0.077 µg/g. The study population had an average fish consumption of 736.0 g/week. The average estimated weekly intakes of MeHg exceeded TWI for some fish consumers including females of childbearing age and those following a high-protein diet. Our study highlights the need to establish regulatory guidelines and dietary advice based on risk/benefit ratio.The study was supported by the central Food laboratory of the ministry of public health.Scopu

Evaluating the invasive plant, Prosopis juliflora in the two initial growth stages as a potential candidate for heavy metal phytostabilization in metalliferous soil

Anthropogenic activities leads to increase in toxic metals in the environment. The toxicity of Cd, Cr and Pb to P. juliflora were tested in agar media; Seeds germinated in 25, 50 and 100 mg/L Pb; 5, 10 and 20 mg/ 10 L Cd; and 10 mg/L Cr were mostly unaffected. At 20 and 40 mg/L, Cr inhibited germination. Similarly, Cd and Cr treatments but not Pb disturbed seedlings development. Up to 3366.3 mg/kg and 1228.6 mg/kg of Pb accumulates in the root and shoot. The bioconcentration factor for both tissues ranged from 27.8 to 115.4 and 11.4 to 45.7, respectively. The translocation factor ranged from approximately 0.4 to 0.5, suggesting that it preferentially accumulates Pb in the root. Fourier Transformed Infrared Spectroscopy confirms Pb ions complexation with functional groups on the plant dry tissue biomass. These findings therefore, suggest that P. juliflora is suitable for Pb phytostabilization in metalliferous soil. Abbreviations: ICP-OES: Inductively Coupled Plasma Optical Emission Spectrometry; FTIR: Fourier Transform Infrared Spectroscopy; BCF: Bioconcentration Factor; TF: Translocation Factor. 2019, 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.The authors wish to acknowledge the Environmental Studies Center (ESC) and Central Laboratory Unit at Qatar University for providing support to ICP-OES and FTIR analysis, respectively. We would like to thank the office of research support at Qatar University's for the student grant QUST-CAS-SPR-2017-33. We also wish to acknowledge Ms. Abeer Al-Muhannadi and Ms. Muneera Al-Mesaifri for their technical support in the Laboratory, as well as identification and collection of plants seeds. The publication of this article was funded by the Qatar National Library.Scopu

Towards Gas Hydrate-Free Pipelines: A Comprehensive Review of Gas Hydrate Inhibition Techniques

Gas hydrate blockage is a major issue that the production and transportation processes in the oil/gas industry faces. The formation of gas hydrates in pipelines results in significant financial losses and serious safety risks. To tackle the flow assurance issues caused by gas hydrate formation in the pipelines, some physical methods and chemical inhibitors are applied by the oil/gas industry. The physical techniques involve subjecting the gas hydrates to thermal heating and depressurization. The alternative method, on the other hand, relies on injecting chemical inhibitors into the pipelines, which affects gas hydrate formation. Chemical inhibitors are classified into high dosage hydrate inhibitors (thermodynamic hydrate inhibitors (THI)) and low dosage hydrate inhibitors (kinetic hydrate inhibitors (KHI) and anti-agglomerates (AAs)). Each chemical inhibitor affects the gas hydrate from a different perspective. The use of physical techniques (thermal heating and depressurization) to inhibit hydrate formation is studied briefly in this review paper. Furthermore, the application of various THIs (alcohols and electrolytes), KHIs (polymeric compounds), and dual function hydrate inhibitors (amino acids, ionic liquids, and nanoparticles) are discussed thoroughly in this study. This review paper aims to provide a complete and comprehensive outlook on the fundamental principles of gas hydrates, and the recent mitigation techniques used by the oil/gas industry to tackle the gas hydrate formation issue. It hopes to provide the chemical engineering platform with ultimate and effective techniques for gas hydrate inhibition. 2022 by the authors.The authors acknowledge the funding from the Qatar University internal grant (QUCG-CENG-21/22-4).Scopu