Adsorptive removal of mercury from water by adsorbents derived from date pits

The current work presented here focuses on the remediation of mercury from water using modified low-cost materials. Modified date pits, low cost, minimal pretreatment steps and locally abundant agricultural waste materials were effectively employed as an adsorbent for remediating Hg2+ from aqueous media. Physical and chemical modification were developed such as thermal roasting (RDP), sulfur (SMRDP) and silane (SIMRDP) based modifications. Results showed that maximum adsorption by RDP was at pH 6, AC and both modifications was at pH 4. Furthermore, RDP has exothermic adsorption mechanism while AC, SMRDP, and SIMRDP have endothermic. All adsorbents except SIMRDP have spontaneous adsorption process. SEM analysis showed that the surface morphology of RDP was not significantly affected by different treatments while surface of AC was affected. The investigation for good adsorbents for Hg2+ uptake from different anthropogenic sources has been carried out by many investigators worldwide towards having a safe environment. In the current study, the highest Hg2+ adsorption of SMRDP was relatively high compared to other known adsorbents. - 2019, The Author(s).This paper was made possible by UREP grant # (17-066-1-004) from the Qatar national research fund (a member of Qatar foundation). The statements made herein are solely the responsibility of the author(s). The authors would like to thank the Environmental Science Center – Qatar University in analyzing mercury ions in the samples, and the Central Laboratory Unit at Qatar University for performing the FTIR and SEM for the samples. The authors would also thank Dr Basem Shomar, Ms. Fatma Fahraei, Ms. Mariem Safi, Ms. Sana Khan, Ms. Maymoona Ayesh, and Ms. Haya Alduroobi for their participation in this UREP project. Special thanks to Mr. M. Y. Ashfaq for his efforts in reading the final version of the manuscript. The publication of this article was funded by the Qatar National Library.Scopu

Development of novel thin film composite reverse osmosis membranes for desalination

Microporous Polyetherimide (PEI) membranes were prepared by wet phase inversion at different temperatures. The thin film composites (TFC) of polyamide on microporous PEI were prepared using meta-Phenylenediamine (MPD) and 1,3,5-Benzenetricarbonyl chloride (BTC). The ATR FTIR characterization showed the formation of polyamide (PA) on microporous PEI membrane, whereas scanning electron microscopy (SEM) revealed that a thin film of polyamide is formed on microporous PEI. The cross-sectional SEM of PEI prepared at 60 °C, showed finger like morphology and sparingly distributed balloon like morphology for PEI synthesized at 80 °C. The performance of PEI membranes and PA TFCs were ascertained by studying permeation of water and rejection of sodium chloride by reverse osmosis. The polyamide TFC with hydrophobic PEI support structures exhibited permeation of 28 to 50 lm-2h-1, with 98 – 95 % 2000 ppm NaCl rejection at 60 bar pressure

Vertical distribution and radiological risk assessment of 137Cs and natural radionuclides in soil samples

The aims of this study were to investigate the vertical distributions of natural radionuclides 232Th, 226Ra and 40K as well as anthropogenic radionuclide 137Cs in soil samples and to analyze the correlation among the radioactivity of these radionuclides and the physiochemical characteristics of soil samples namely pH, grain size, carbonate content and organic matter. Risk assessment of the radiological hazard has also been estimated. Forty-four soil samples were collected from eleven locations in Qatar at four depth levels from 0 to 16 cm. The average concentrations of 232Th, 226Ra, 40K and 137Cs in the soil depth of 16 cm were 10, 17, 201 and 4 Bq/kg, respectively, which were within the reported world mean. The external absorbed gamma dose rate, the annual effective dose, the mean radium equivalent activity, the external hazard index and the lifetime cancer risk were 22 nGy/h, 0.027 mSv/y, 47 Bq/kg, 0.125 and 0.096 × 10−3, respectively. These values were far below the minimum recommended international values. The level of radioactivity concentrations in the soil was affected by the physiochemical characteristics of the soil. The positive correlation with highest R2 value was found among the radioactivity concentrations of 232Th and 40K and the soil clay content. Total organic carbon was also positively correlated for 226Ra and 137Cs activity concentrations, whereas, carbonate content was negatively correlated with the radioactivity concentrations of 232Th and 40K. As far as soil moisture content is concerned, the positive correlation with highest R2 value was obtained for 226Ra activity concentrations. © 2019, The Author(s).The authors wish to acknowledge the Environmental Science Center (ESC) and Central Laboratory Unit at Qatar University for providing support to physiochemical characteristics of the collected soil samples. We also thanks the ministry of municipality and environment-radiation and chemical protection for analyzing the radioactivity concentration. The publication of this article was funded by the Qatar National Library.Scopu

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

A better understanding of seawater reverse osmosis brine: Characterizations, uses, and energy requirements

Before investing in any optimizing technology for the recovery and reuse of brine resources, it is of importance to study the full physicochemical characteristics of the brine. In the current study, the physicochemical characteristics of Qatari seawater reverse osmosis (SWRO) brine were fully investigated. The current study intends to lead to a better understanding of the nature of SWRO brine given the economic significance for the country that can be benefited from recycling and reusing various components. The characterization includes physical and chemical composition, as well as mineralogical and morphological investigation. The chemical analysis revealed that the seawater reverse osmosis brine contains various valuable elements and metals such as Ca (77120 mg/L), Na (343500 mg/L), Li (238800 mg/L), Ba (3.3 mg/L), Cs (3.4 mg/L), Fe (30.5 mg/L) and Mg (238800 mg/L). The pH of the brine was 8, while the electrical conductivity and salinity were 90.56 mS/cm and 61.4 ppt, respectively. The scanning electron microscopy-energy-dispersive and energy-dispersive X-ray revealed the placement of various valuable metals on the salt surface. X-ray diffraction showed eight XRD peaks. Interestingly, one peak at 2? of 31.7� is significantly more intense than the other seven peaks obtained, while all the eight peaks are extremely narrow. The Fourier-transform infrared spectroscopy analysis of the brine sample showed the presence of various functional groups. The narrow and intense peak around 1408 cm?1 confirms the presence of the S[dbnd]O bond in the brine sample, which could correspond to the presence of sulfonyl chlorides or sulfates as indicated by the ICP-OES results. Furthermore, a comparison between the energy requirements for the widely used seawater desalination technologies was presented. Additionally, this study showed the economical and environmental advantages and potential for recovering valuable metals from seawater reverse osmosis brines.Scopu

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

From Waste to Watts: Updates on Key Applications of Microbial Fuel Cells in Wastewater Treatment and Energy Production

Due to fossil fuel depletion and the rapid growth of industry, it is critical to develop environmentally friendly and long-term alternative energy technologies. Microbial fuel cells (MFCs) are a powerful platform for extracting energy from various sources and converting it to electricity. As no intermediate steps are required to harness the electricity from the organic substrate?s stored chemical energy, MFC technology offers a sustainable alternative source of energy production. The generation of electricity from the organic substances contained in waste using MFC technology could provide a cost-effective solution to the issue of environmental pollution and energy shortages in the near future. Thus, technical advancements in bioelectricity production from wastewater are becoming commercially viable. Due to practical limitations, and although promising prospects have been reported in recent investigations, MFCs are incapable of upscaling and of high-energy production. In this review paper, intensive research has been conducted on MFCs? applications in the treatment of wastewater. Several types of waste have been extensively studied, including municipal or domestic waste, industrial waste, brewery wastewater, and urine waste. Furthermore, the applications of MFCs in the removal of nutrients (nitrogen and sulphates) and precious metals from wastewater were also intensively reviewed. As a result, the efficacy of various MFCs in achieving sustainable power generation from wastewater has been critically addressed in this studyScopu

Hydrogeochemical characterization and quality evaluation of groundwater suitability for domestic and agricultural uses in the state of Qatar

This study aims to investigate the groundwater (GW) quality in Qatar to be utilized in domestic and agricultural uses. The integrated physiochemical analysis along with hydrochemical faces analysis, geochemical modeling, statistical and geostatistical analysis was conducted. The results showed that the GW samples mainly have the following cations Na+ > Ca2+ > Mg2+ >K+ abundantly, while Cl− > SO42− > HCO3− > NO3− were the main anions. The obtained analytical values of the GW samples were plotted on Piper, Schoeller, Ternary, Ludwig Langelier, Giggenbach Triangle, Durov, and stiff graphs. The hydrogeochemical facies and the obtained graphs confirmed that most of the analyzed GW samples fall into two types of water namely calcium-chloride-type (SO4–Cl and Ca–Mg) and sodium-chloride-type (SO4–Cl and Na–K). Three principal components were yielded from the principal component analysis (PCA), which are the first principal component (PC1), second principal component (PC2), and third principal component (PC3) with ≥1 Eigenvalues, and total variance of 49, 31, and 19.9%, respectively. A positive loading of Mg, Th, Sr, Ca, TDS, SO4, Li, Cl, F, Br, Cd, K, Ba, and Na has been shown by the PC1; representing the factors which are contributing to the high salinity of the GW due to the salt water intrusion and the mineralization of rocks and soil which is supported by the water type classification and saturation indices. The PC2 showed a negative loading of U, Al, Se, Mo, Mg, and temperature, which could be associated with a localized sedimentary depositional or hydrogeochemical environment. The PC3 showed a positive loading of Ni, Zn, Be, pH, Cu, Co, Fe, B, V, and TOC, which indicates the dissolution and precipitation (reducing and oxidizing factor) such as iron which is a redox-sensitive variable.Scopu

Development of industrially viable geopolymers from treated petroleum fly ash

This paper investigates the development of stable geopolymers using petroleum fly ash with high compressive strength and water absorption to promote cleaner production, sustainability, and recycling of waste. The paper provided detailed characterizations of the petroleum fly ash, which involved the determination of the particle size diameter, density, surface area, pore-volume, mineralogical identification of recording X-ray diffraction pattern, X-ray fluorescence, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscope. Moreover, metals leachability from the petroleum fly ash using different extracting agents, namely H2SO4, H3PO4, (NH4)2SO4, NH4NO3, and NH4O2CCO2H was also considered. Five geopolymers were prepared using different amounts of petroleum fly ash to assess the influence of petroleum fly ash on the final performance of the prepared geopolymers. The results revealed that the petroleum fly ash was carbonaceous in nature and rich in vanadium oxide and nickel oxide with low in SiO2 and Al2O3. Furthermore, it was found that petroleum fly ash has a low calcium level. The maximum extraction values were 15.6% for V and 55.6% for Ni using H2SO4. All the prepared geopolymers displayed high compressive strength for longer curing times, and the water absorption properties of all geopolymers were improved by incorporating more petroleum fly ash. Increasing the petroleum fly ash from 0 vol% to 61 vol% increased the water absorption value from 6.6 to 13.3 wt% for the samples collected after 28 days of curing. It was concluded that the petroleum fly ash did tend to form successful stable geopolymers with high compressive strength and water absorption.Scopu

Recent developments and advancements in graphene-based technologies for oil spill cleanup and oil-water separation processes

The vast demand for petroleum industry products led to the increased production of oily wastewaters and has led to many possible separation technologies. In addition to production-related oily wastewater, direct oil spills are associated with detrimental effects on the local ecosystems. Accordingly, this review paper aims to tackle the oil spill cleanup issue as well as water separation by providing a wide range of graphene-based technologies. These include graphene-based membranes; graphene sponges; graphene-decorated meshes; graphene hydrogels; graphene aerogels; graphene foam; and graphene-coated cotton. Sponges and aerogels modified by graphene and reduced graphene oxide demonstrated effective oil water separation owing to their superhydrophobic/superoleophilic properties. In addition, oil particles are intercepted while allowing water molecules to penetrate the graphene-oxide-coated metal meshes and membranes thanks to their superhydrophilic/underwater superoleophobic properties. Finally, we offer future perspectives on oil water separation that are hindering the advancements of such technologies and their large-scale applications.Scopu