Alumina Membranes for Desalination and Water Treatment

In recent years, there has been a growing interest in utilizing inorganic membranes, particularly alumina (Al2O3) ceramic membranes (CMs), and to address a variety of separation problems in miscellaneous industry. Al2O3 membranes are commercially predominant in CMs market. Al2O3 material is generally used either as membrane support and/or as membrane layer due to advantages provided by this material and its derivatives such as availability in tonnage quantities, chemical inertness, good hardness, and thermal stability of the porous texture during elaboration steps. In this chapter, we comprehensibly look at the recent studies related to desalination and water treatment by ultrafiltration (UF), nanofiltration (NF) Al2O3 membrane, and highlight the separation properties of the membrane in specific environmental pollution. The influences of membrane operating conditions and water quality on the rejection of pollutant by Al2O3 membrane are reported through a series of bench-level experiments

In-depth exploration of defects in zeolite membranes: Typology, formation, characterization and healing

International audienceUnlocking the potential of zeolite membranes consists in overcoming the persistent challenge of defects formation, a barrier against their application at industrial scale. Understanding the mechanisms underlying defects formation is mandatory for achieving precise control and optimization of membrane performance. This paper offers a comprehensive exploration of the diverse defects of zeolite membranes, investigating the factors responsible for their occurrence during membrane preparation such as crystallization kinetics, seeding techniques and template removal. Furthermore, a variety of characterization techniques used to identify defects are examined, highlighting their features and drawbacks. This review also explores the current strategies to heal defects, including post-treatment methods and preparation optimization. Through this elucidation, the paper aims to make a progress in addressing the defect issue in zeolite membranes

Fabrication of flat ceramic microfiltration membrane from natural kaolinite for seawater pretreatment for desalination and wastewater clarification

International audienceThe aim of this work is the manufacturing of flat microfiltration membrane made from Moroccan natural kaolinite clay and corn starch as porosity agent. The membrane was prepared by uniaxial pressing technique and sintering at 1,100 degrees C. The effect of starch on membrane features was investigated from 0 to 15 wt.%. The membrane has a diameter of 37.8 mm and a thickness of 2.3 mm. In order to optimize its properties, prepared membrane was characterized in terms of apparent porosity, water absorption, apparent density, mechanical strength, pore size, microstructure, and water permeability measurements. Experimental results showed that the membrane prepared with 10 wt.% of starch is considered as an optimized membrane which has an average pore size of 2.3 mu m, the mechanical strength of 20.2 MPa, and permeability of 2,129 L h(-1)m(-2) bar(-1). The optimized membrane was applied for pretreatment of raw seawater for desalination and clarification of agro-food effluent using dead-end filtration under pressure of 0.12 bar. Filtration results showed that turbidity rejection achieves 73% and 99%, respectively for raw seawater and agro-food model effluent

Electrochemical sensor based on low silica X zeolite modified carbon paste for carbaryl determination

A new and simple approach for carbaryl determination in natural sample was proposed using Low Silica X (LSX) zeolite modified carbon paste electrode. LSX zeolite with a porous structure was incorporated into carbon paste electrode in the appropriate portion. The prepared electrode was then characterized using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters as the zeolite amounts, pH, accumulation time, and differential pulse voltammetric parameters were optimized. Under optimal conditions, a linear response was obtained in the range of 1–100 µM of carbaryl using differential pulse voltammetry with detection limit of 0.3 µM (S/N = 3). The sensors showed good selectivity, stability, and reproducibility and has been successfully applied for detection of carbaryl in tomato samples with good recoveries

Enhancing stability and performance of graphene oxide membrane grafted on low-cost rich-silica support: a comparative study of two activation approaches

International audienceAlthough graphene oxide has shown encouraging results in membrane field, it has a major stability issue when coated on ceramic supports, particularly those formed of geomaterials. This work aims to prepare stable graphene oxide layer deposited on a low-cost rich-silica support. The graphene oxide membrane was prepared using grafting method, which included surface activation and modification followed by the graphene oxide layer coating. Siloxane functional groups were activated using either hydrochloric acid or piranha solution to determine which of them provided the highest membrane stability. The support surface was chemically modified using 3-glycidoxypropyltrimethoxysilan followed by the deposition of graphene oxide nanosheets using evaporation-assisted assembly. According to Fourier-transform infrared spectroscopy, the support activated with piranha solution has more silanol functional groups than the support activated with hydrochloric acid while the appearance of 3-glycidoxypropyltrimethoxysilan band on the modified support, proves the accomplishment of grafting. The stability test of the membrane demonstrated a highly stable deposited layer for the graphene oxide membrane activated with piranha solution in different pH contrary to the non-grafted graphene oxide membrane and the graphene oxide membrane activated with hydrochloric acid that peeled off from the support. On the support activated with piranha solution, 3-glycidoxypropyltrimethoxysilan concentration was investigated and an optimal value of 0.1 mol L−1 was determined. The filtration performance of the membrane was assessed by the removal of anionic and cationic dyes. For anionic dyes, the membrane rejection reached a value of 90 % for direct red 80 and 87 % for methyl orange. For the rhodamine B considered as cationic dye, the membrane rejection reached a value of 81 %. The membrane may be considered sustainable since it is inexpensive and emits at least 9.76 kg CO2eq m−2 less than other ceramic membranes during its preparation