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

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

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

Development of Polymer Modified Graphene Oxide Nanocomposite Membranes to Reduce both Scaling and Biofouling

In seawater reverse osmosis (SWRO), membrane scaling is one of the major issues affecting its widespread application in the desalination industry. In this research, the effect of concentration of calcium and sulfate ions from 20 to 150 mM and temperature from 5 to 35?C on calcium sulfate scaling of reverse osmosis (RO) and Graphene oxide functionalized RO membranes was investigated. It was found that increase of concentration as well as temperature enhances the mineral scaling, where morphology of crystals varies from rod shaped to rosette structures. It was also observed that commonly found seawater bacteria can use antiscalants as an energy/carbon source thereby degrading them and reducing their efficiency to reduce mineral scaling. Moreover, bacteria were found to be capable of inducing/mediating calcium sulfate precipitation on RO membranes, further enhancing the mineral scaling. Therefore, it was important to modify RO membranes capable of simultaneously reduce both mineral scaling and biofouling. For this purpose, RO membrane was modified with antibacterial graphene oxide and polymer antiscalants using microwave radiation technique. It was found that the modified membranes were able to inhibit microbial growth up to 95%, while, mineral scaling was also reduced by 97%. Hence, it was concluded that the coating of polymer modified graphene oxide nanocomposites on RO membranes can simultaneously reduce both biofouling and scaling. So far, such dual characteristics of modified membranes have not been reported in the literature

Valorization of palm tree (Phoenix dactylifera L.) leaves from harsh weather climate by silage using endogenous lactic acid bacteria, and application of MALDI-TOF MS for study of populations dynamics

Preservation of green palm leaves by silage preserves them as green feed in addition to the added value of probiotics and prebiotics. In this work, the characterization of fresh palm tree leaves was performed. The isolation of local lactic acid bacteria allowed selection of 4 isolates for the silage of the palm tree leaves. Dairy feed was used to enrich the leaves silage with the necessary nutrients. Lactobacillus paracasei and Pediococcus acidilactici were found to be dominating their respectively inoculated silages. The high occurrence of LAB found in the spontaneous silages of the palm tree leaves mixed with dairy feed is a good indication that ensiling palm tree leaves can support the growth of LAB and produce good-quality silage. However, a combination of the process by following the population dynamics using MALDI-TOF MS allowed the selection of the appropriate LAB strain, which is a new approach for application of silage.The publication of this article was funded by the Qatar National Library.Scopu

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

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