Determination of some physico-thermal and mechanical characteristics of hydrated Jordanian Lajjun oil shale ash

The hydration of oil shale ash at different water-to-ash weight (W/A) ratios ranging from 0.4 to 0.8 was experimentally investigated. The ash hydrateâs physical characteristics, its particlesâ elemental composition, and the existing crystalline phases were identified using N2 Brunauer-Emmerich-Teller (N2-BET), Energy Dispersive X-ray (EDX) and X-ray Powder Diffraction (XRD) measurement techniques. The formed hydration cementitious products were found to be stratlingite (2CaO·Al2O3·SiO2·8H2O), ettringite (6CaO·Al2O3·3SiO3·32H2O), and melilite (2CaO·Al2O3·SiO2 ) in the oil shale ash hydrated at W/A = 0.6. These same phases with different relative amounts were found in the oil shale ash hydrated at W/A = 0.8 in addition to calcium silicate hydrates (CSH). The drop in the physico-thermal properties (bulk density and thermal conductivity) of the hydrated ash was attributed to the formation of cementitious products, mainly to stratlingite, melilite, and ettringite. The hydrated ashâs mechanical properties (bending and compressive strengths) were found to increase at higher W/A due to the formation of cementing materials, particularly CSH

Influence of operating parameters on electrocoagulation of C.I. disperse yellow 3

This work deals with the electrocoagulation (EC) process for an organic dye removal. The chosen organic dye is C.I. disperse yellow 3 (DY) which is used in textile industry. Experiments were performed in batch mode using Al electrodes and for comparison purposes Fe electrodes. The experimental set-up was composed of 1 L beaker, two identical electrodes which are separated 2 cm from each other. The main operating parameters influencing EC process were examined such as pH, supporting electrolyte concentration CNaCl, current density i, and DY concen­tration. High performance EC process was shown during 45 min for 200 mg/L dye concentration at i = 350 A m-2 (applied voltage 12 V) and CNaCl = 1 g L-1 reaching 98 % for pHs 3 and 10 and 99 % for pH 6. After 10 min, DY was also efficiently removed (86 %) showing that EC process may be conveniently applied for textile industry wastewater treatment. EC using Fe electrodes exhibited slightly lower performance comparing EC using Al electrodes

The hydrophilic/hydrophobic ratio vs. dissolved organics removal by coagulation – A review

This review discusses the hydrophilic/hydrophobic ratio as a function of the hydrophilic and hydrophobic contents removal by coagulation process. It is well established that coagulation process could bring a reduction in dissolved organic carbon of around 30–60% by increasing the coagulant dose and optimising reaction pH, in which large organic molecules with hydrophobic property was removed preferentially. Furthermore, the literature affirmed that the greater removal of UV-absorbing substances indicates that alum coagulation preferentially removed the hydrophobic fraction of the total organic carbon. For the hydrophobic fraction, it needs to be removed entirely without its transformation into hydrophilic fractions by coagulation process avoiding pre-chlorination/pre-oxidation due to the risk of organic molecules fragmentation. Determining the exact numerical values of the hydrophilic/hydrophobic ratio for raw water and treated water at different stages of the treatment processes in a water treatment plant, as for the DCO/DBO5 ratio in the case of wastewater treatment, would help on more focusing on OM control and removal

Applying Chitin Enhanced Diafiltration Process (CEFP) in Removing Cobalt from Synthetic Wastewater

This research aims to study the removal of Cobalt (Co) using chitin. The optimum conditions for removing Co were ascertained through batch experiments. This study involves the determination of chitin metal-binding efficiency by using a polymer enhanced diafiltration setup that utilizes a membrane process (ultrafiltration) to keep the Chitin. The effects of several parameters on sorption like pH, the concentrations of chitin, and Co were examined. The best efficiency was reached if the setup was run at pH Ka). At acidic conditions and by employing 6 g/L of chitin, Co level (20 mg/L) was decreased at 95%. To further investigate the kinetics of sorption for each gram of chitin, equilibrium experiments were carried out. For 1–100 mM Co, the performed rheological measurements show that chitin was observed to be moderately shear thickening at relatively lower levels (4 and 6 g/L); further, it was moderately shear thinning at slightly more important levels (12 and 20 g/L). Some improvement of the raw polymer will be necessary to enhance sorption to a sustainable limit and make this scheme an economically viable process

Legionella: Health Impacts, Exposure Evaluation, and Hazard Reduction

Legionella pneumophila is an intracellular pathogen, omnipresent in the nature and seen as opportunistic. It is the main source of legionellosis that can take place in its nonpneumonic form (Pontiac fever) and acute pneumonic form (Legionnaires’ disease). In the aquatic systems, L. pneumophila can conquer and remain alive intracellularly in different protozoans. The faculty to multiply inside biofilms gives more safeguard from natural stresses like disinfection. Human contagion by L. pneumophila happens following the inhalation or aspiration of aerosols carrying the pathogen. This work defines microbiologically Legionella bacteria and presents a brief history relating to their first discovery and following contagions, a short description relating to their metabolism and physiology, a discussion of their clinical characteristics and their subsistence in the nature and growth in a biofilm, and a general examination of numerous technologies employed for their removal. The spread of opportunistic pathogens (OPs) remains the most significant feature of microbial potable water quality besides the generation of disinfection by-products (DBPs). The (re)growth of OPs and the production of DBPs in urban engineered water systems both closely correlate with the injections or concentrations of disinfectant residuals. Nonetheless, OPs and DBPs respond to disinfectant residuals frequently oppositely. An elevated residual concentration efficiently suppresses the (re)growth of OPs while intensifies the production of DBPs. Oppositely, a low or “detectable” disinfectant residual level decreases the generation of DBPs but could not stop OPs from thriving. To guarantee that the overall or combined health risks of OPs and DBPs are minimum, OP (re)growth and DBP generation must be deeply revised while selecting a practical disinfectant residual dosage or level

Towards a novel EMHD dissipative stagnation point flow model for radiating copper-based ethylene glycol nanofluids: An unsteady two-dimensional homogeneous second-grade flow case study

A novel EMHD dissipative second-grade nanofluid flow model is proposed exclusively in this numerical inspection for radiating copper-based ethylene glycol nanofluids to reveal the dynamical and thermal aspects of the studied homogeneous mixture during its unsteady two-dimensional stagnation point flow towards a horizontal electromagnetic actuator. Based on admissible physical assumptions and authenticated experimental correlations, the governing PDEs and BCs are derived appropriately for the nanofluid flow problem under consideration. After numerous rearrangements and non-dimensionalization treatments, the resulting ODEs and BCs are handled computationally with the help of a robust GDQ algorithm under the parametric control of several influencing factors, whose strengthening magnitudes affect probably the flow control process and heat transport mechanism. In this context, it proved graphically that the nanoparticles’ loading process exhibits dissimilar dynamical and thermal impacts as compared with the influences of the nanoparticles’ diameter size. Besides, the resistive dynamical effect of the utilized electromagnetic actuator reinforces thermally the enhancing role of the thermal radiative heat flux and Joule’s heating process within the nanofluidic medium

Simulating two Algerian cities' desalination plants coupled with solar energy systems using TRNSYS

Our study aimed to design a prototype for a desalination unit coupled with a solar collector, utilizing TRNSYS 16, to address the needs of both Bouzaréah in northern Algeria and Ghardaïa in southern Algeria. The desalination unit is composed of vacuum membrane distillation (VMD) coupled with a solar collector, and the photovoltaic has been designed according to the climatic conditions of each region. In this work, the approach adopted is to integrate a model developed in the literature into a simulation environment (TRNSYS) coupled with the CODE-BLOCKS compiler and FORTRAN programming language to create a new component (i.e., VMD process). Simulation results showed that the optimum permeation flux obtained through the desalination unit is relatively higher in Ghardaïa than in Bouzaréah, with a flow exceeding 30 kg/h.m2. The permeation flux and the power to load reached their maximum values with the charge of solar irradiation 48 kg/h.m2 and 6300 kJ/h, respectively, for Ghardaïa at the sun irradiation value 800 W/m2 and temperature of 34 °C. Results showed that Ghardaïa had a higher GOR value than Bouzaréah over the year (10.947 vs. 8.3389). Moreover, both locations recorded thermal recovery ratio values exceeding 1, indicating the high efficiency of the desalination unit. HIGHLIGHTS A model that describes the evolution of feed temperature and permeation flux through the membrane was integrated into TRNSYS as a VMD module.; Empirical correlations were developed based on experimental results recorded at a meteorological station in two different cities.; The plant was designed to conduct annual simulations in two different cities under specific operating conditions.

Analysis of a Ferromagnetic Nanofluid Saturating a Porous Medium with Nield’s Boundary Conditions

This research delves into the intricacies of a two-dimensional, steady flow of a ferrofluid within a porous medium, where the thermal conductivity is subject to temperature variations. The study encompasses the influence of magnetic dipoles, radiation, Brownian motion, and thermophoresis phenomena as they interact with a stretching sheet. A novel aspect of this investigation is the detailed analysis of Brownian and thermophoresis effects on nanoparticles while considering Nield’s boundary conditions. The study involves the transformation of flow equations into ordinary differential equations through standard similarity transformations, unraveling the governing equations using the BVP4C method. The outcomes are presented graphically, providing a comprehensive assessment of the factors impacting the fluid properties, including velocity, temperature, and concentration. Notably, this study reveals that an increase in the ferrofluid parameter leads to elevated temperature profiles while causing a decrease in velocity. Furthermore, an increase in the viscosity parameter is associated with a reduction in velocity. Some technological applications of the problem include magnetically controlled actuation and drug targeting