Predictors of Literacy and Attitudes Toward Reading Among Syrian Refugee Children in Jordan

Refugee children often face disruptions to their education before and during displacement. However, little is known about either levels or predictors of refugee children’s literacy or about their attitudes toward reading in low- or middle-income countries. To address this, we conducted in-home literacy assessments using the Holistic Assessment of Learning and Development Outcomes with 322 Syrian refugee mother–child dyads who lived in Jordan (child age range 4–8 years, M = 6.32 years, 50% female). Overall, the children had quite low levels of literacy, although they indicated a strong enthusiasm for reading. Child age, maternal education, and maternal ability to read all predicted child literacy, although maternal literacy predicted it only among children enrolled in school. Among those enrolled in school (64.9% of the total sample, 88.7% of those aged ≥ 6), students attending hybrid classes had better literacy than those attending either solely in-person or solely online, although the frequency of school attendance did not predict literacy. A less consistent pattern emerged for predicting children’s attitudes toward reading. Our results suggest an urgent need to improve literacy skills among refugee children in Jordan, as well as a need for validated measures of attitudes toward reading for use with Arabic-speaking youth. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13158-022-00334-x

Performance of PES/LSMM-OGCN photocatalytic membrane for phenol removal: effect of OGCN loading

In designing a photocatalytic oxidation system, the immobilized photocatalyst technique becomes highly profitable due to its promising capability in treating organic pollutants such as phenols in wastewater. In this study, hydrophiLic surface modifying macromolecules (LSMM) modified polyethersulfone (PES) hybrid photocatalytic membranes incorporated with oxygenated graphitic carbon nitride (OGCN) was successfully developed using phase inversion technique. The effectiveness of the hybrid photocatalytic membrane was determined under different loading of OGCN photocatalyst (0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%). The best amount of OGCN in the casting solution was 1.0 wt% as the agglomeration did not occur considering2·h the stability of the membrane performance and morphology. The highest flux of 264 L/m was achieved by PES/LSMM-OGCN1.5wt% membrane. However, the highest flux performance was not an advantage in this situation as the flux reduced the rejection value due to open pores. The membrane with the highest photocatalytic performance was obtained at 1.0 wt% of OGCN loading with 35.78% phenol degradation after 6 h. Regardless of the lower rejection value, the performance shown by the PES/LSMM-OGCN1.0wt% membrane was still competent because of the small difference of less than 1% to that of the PES/LSMM-OGCN0wt% membrane. Based on the findings, it can be concluded that the optimisation of the OGCN loading in the PES hybrid photocatalytic membrane indeed plays an important role towards enhancing the catalyst distribution, phenol degradation, and acceptable rejection above all considerations

Guidelines for preparation of higher flux hydrophobic/hydrophilic composite membranes for membrane distillation

For the first time, a mathematical model is presented to validate the hydrophobic/hydrophilic composite membrane concept in membrane distillation (MD). This mathematical model aims at providing the optimal characteristics of both hydrophobic and hydrophilic layers as well as giving the guidelines to prepare highly efficient MD membranes. The model was tested by the experimental data obtained from four laboratory-made and two commercial membranes. A very good agreement between the experimental and theoretical values for the vapour fluxes was obtained. In addition, the effect of morphological characteristics of both hydrophobic top-layer and hydrophilic sub-layer was studied by simulating the permeate flux, when the membranes were used for direct contact membrane distillation (DCMD). Those characteristics include hydrophobic top-layer porosity and hydrophilic sub-layer porosity, thicknesses of the hydrophobic and hydrophilic layers and their thermal conductivity. Throughout the proposed model, a criterion parameter (f(i)) reflecting the hydrophobic top-layer and hydrophilic sub-layer morphology was identified. It was found that the criterion parameter (f(i)) should be lower than unity in order to improve the permeate flux by increasing the hydrophilic sub-layer thickness when the total membrane thickness is constant. All the tested membranes in this study satisfied this requirement. The simulation further indicated that, the calculated DCMD theoretical flux increased enormously with increasing the hydrophilic sub-layer thickness. Moreover, the theoretical flux increased with increasing both the hydrophobic and hydrophilic layers' porosities, but it was more pronounced for the hydrophobic top-layer porosity. It was also found that the permeate flux is highly enhanced by increasing the sub-layer thermal conductivity at infinite heat transfer coefficients, but this effect was less pronounced when the heat transfer coefficients are not infinity

Novel porous composite hydrophobic/hydrophilic polysulfone membranes for desalination by direct contact membrane distillation

Novel composite membrane distillation membranes were prepared by blending the hydrophilic polysulfone with hydrophobic surface modifying macromolecules (SMMs). Three different types of SMMs were tested. These SMMs were synthesized and characterized for fluorine content, molecular weights and glass transition temperature. Phase inversion method in a single casting step was used to prepare the composite membranes. The membranes were characterized by means of different techniques such as contact angle measurement, gas permeation test, liquid entry pressure of water and scanning electron microscopy. Finally, these membranes were tested for desalination by direct contact membrane distillation (DCMD). Different membrane preparation conditions affecting membrane morphology, structure and DCMD performance were investigated. The parameters studied were the SMMs type, polysulfone concentration, solvent type and non-solvent additive concentration in the casting solution. Attempts linking the membrane morphology to its DCMD performance have been made. it was found that increasing the polymer concentration or the non-solvent additive concentration decreased the permeate flux of the porous composite hydrophobic/hydrophilic membranes since the liquid entry pressure of water increased and the ratio of the membrane pore size time the porosity over the effective pore length (r epsilon/L(p)) decreased. Furthermore, the stoichiometric ratio of the SMMs, type of SMMs, was found to affect considerably the characteristics and permeate flux of the composite membranes. In general, the composite membranes with higher liquid entry pressure of water exhibited smaller permeate fluxes. Moreover, the obtained results were compared to those of a commercial polytetrafluoroethylene membrane and it was observed that some of the SMMs blended polysulfone membranes achieved better DCMD fluxes than those of the commercial membrane. A permeate flux 43% higher than that of the commercial membrane was achieved with 99.9% NaCl separation factor

Preparation and characterization of novel hydrophobic/hydrophilic polyetherimide composite membranes for desalination by direct contact membrane distillation

Two different types of hydrophobic surface modifying macromolecules (SMMs) were synthesized and characterized for fluorine content, average molecular weight and glass transition temperature. The synthesized SMMs were blended into polyetherimide (PEI) hydrophilic host polymer to form porous hydrophobic/hydrophilic composite membranes by the phase inversion method. The prepared membranes were characterized by the contact angle measurements, X-ray photoelectron spectroscopy test, gas permeation test, liquid entry pressure of water and scanning electron microscopy. Finally, these membranes were tested for desalination by direct contact membrane distillation (DCMD). Different parameters affecting the membrane preparation process were studied and their effects on the membrane morphology as well as on the membrane performance in clesalination by DCMD were identified. These parameters include the SMMs type, SMMs concentration, solvent type and solvent evaporation time before gelation. An attempt to link the membrane morphology to its performance in DCMD is presented. This leads to better understanding of the effect of the membrane preparation on its performance. it was found that increasing the solvent evaporation time before gelation decreased the membrane flux since smaller pore sizes were observed. The membranes with higher contact angles and fluorine contents (more hydrophobic) exhibited smaller permeate fluxes. The membranes having sponge-like structures at the hydrophilic layer exhibited higher fluxes than those having finger-like structure at the hydrophilic layer. Moreover, the results were compared to a commercial polytetrafluoroethylene (PTFE) membrane. It was observed that most of the SMMs blended PEI membranes achieved better DCMD fluxes than those of the commercial membrane. A permeate flux 55% higher than that of PTFE was achieved. For both PTFE commercial membrane and all SMMs blended PEI membranes, the NaCl separation factor was found to be higher than 99% except for the PEI membrane prepared without SMMs

Effect of casting conditions on SMM blended polyethersulfone hydro-phobic/philic composite membranes: characteristics and desalination performance in membrane distillation

This study aims at further improvement and development of the novel hydro–phobic/–philic composite membranes which are made specifically for membrane distillation (MD). This was attempted by studying the effect of the casting conditions during the membrane preparation process by the phase inversion method. Two variables were chosen to study, which are the evaporation time before gelation and the gelation path temperature. Some of the membranes were allowed to evaporate at room temperature for 2 or 3 minutes to study the effect of evaporation time. The temperature of the gelation path was varied to 4°C, 20°C or 60°C in order to study the gelation path temperature effect. The prepared membranes were characterized using gas permeation test, measurement of the liquid entry pressure of water (LEPw), X–ray photoelectron spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM). The effects of the casting conditions on the membrane morphology were identified, which enabled us to link the membrane morphology to the membrane performance. The membranes were then tested for desalination of 0.5 M NaCl solution by direct contact membrane distillation (DCMD) and the results were compared to commercial polytetraflouroethylene (PTFE) membrane. It was found that the membrane which was prepared with no evaporation time produced better flux than those with evaporation time. Regarding the gelation path temperature; the membrane prepared with gelation path temperature of 4°C was better than those prepared with gelation path temperature of 20 or 60°C. It should be emphasized that the DCMD flux of the membranes prepared with no evaporation time or with a gelation path temperature of 4°C was superior to the commercial one. Furthermore, all the prepared membranes were tested successfully for the desalination application. In other words, no NaCl was detected in the permeate

Effect of surface modifying macromolecules stoichiometric ratio on composite hydrophobic/hydrophilic membranes characteristics and performance in direct contact membrane distillation

The stoichiometric ratio for the synthesis components of hydrophobic new surface modifying macromolecules (nSMM) was altered systematically to produce three different types of nSMMs, which are called hereafter nSMM1, nSMM2, and nSMM3. The newly synthesized SMMs were characterized for fluorine content, average molecular weight, and glass transition temperature. The results showed that fluorine content decreased with increasing the ratio of alpha,omega-aminopropyl poly(dimethyl siloxane) to 4,4'-methylene bis(phenyl isocyanate). The synthesized nSMMs were blended into hydrophilic polyetherimide (PEI) host polymer to form porous hydrophobic/hydrophilic composite membranes by the phase inversion method. The prepared membranes were characterized by the contact angle measurement, X-ray photoelectron spectroscopy, gas permeation test, measurement of liquid entry pressure of water, and scanning electron microscopy. Finally, these membranes were tested for desalination by direct contact membrane distillation and the results were compared with those of commercial polytetraflouroethylene membrane. The effects of the nSMM type on the membrane morphology were identified, which enabled us to link the membrane morphology to the membrane performance. It was found that the nSMM2/PEI membrane yielded the best performance among the tested membranes. In particular, it should be emphasized that the above membrane was superior to the commercial one

Comparing the desalination performance of SMM blended polyethersulfone to SMM blended polyetherimide membranes by direct contact membrane distillation

This study aims to compare the effect of host hydrophilic polymer on novel hydrophobic/hydrophilic composite membrane characteristics and desalination performance by direct contact membrane distillation (DCMD). Two different polymers are used for the host polymer: polyethersulfone (PES) and polyetherimide (PEI). The membranes were prepared by the phase inversion method by blending surface modifying macromolecules (SMM) into the host hydrophilic polymer (PES and PEI). The membranes were characterized using a wide variety of characterization techniques including the gas permeation test, measurement of the liquid entry pressure of water (LEPw), scanning electronic microscopy (SEM), atomic force microscopy (AFM) and contact angle measurement. Furthermore, the membranes were tested by DCMD for desalination of 0.5 M NaCl solution and the results were compared to commercial polytetrafluoroethylene (PTFE) membranes (FGLP 1425, Millipore). The effects of the type of host polymer oil membrane morphology and characteristics were identified, which enabled us to link membrane morphology to membrane performance. The PES membrane yielded Superior flux to that of the commercial membrane and the PEI membrane when their performance was compared. This result could be attributed to the fact that the nSMM/PES had a higher pore size/porosity ratio and lower LEPw than the nSMM/PEI membrane. It is worth mentioning that all prepared membranes were tested successfully for the desalination application. hi other words, NaCl concentrations in the permeate were below 200 ppm