Preparation of Sodalite and Faujasite Clay Composite Membranes and Their Utilization in the Decontamination of Dye Effluents

The present work describes the deposition of two zeolite films, sodalite and faujasite, by the hydrothermal method to tune the mesopores of clay support, which are prepared from a widely available clay depot from the central region of Morocco (Midelt). The clay supports were prepared by a powder metallurgy method from different granulometries with activated carbon as a porosity agent, using uniaxial compression followed by a sintering process. The 160 µm ≤ Φ ≤ 250 µm support showed the highest water flux compared to the supports made from smaller granulometries with a minimum water flux of 1405 L.m−2·h−1 after a working time of 2 h and 90 min. This support was chosen for the deposition of sodalite (SOM) and faujasite (FAM) zeolite membranes. The X-ray diffraction of sodalite and faujasite showed that they were well crystallized, and the obtained spectra corresponded well with the sought phases. Such findings were confirmed by the SEM analysis, which showed that SOM was crystalized as fine particles while the FAM micrographs showed the existence of crystals with an average size ranging from 0.53 µm to 1.8 µm with a bipyramidal shape and a square or Cubo octahedral base. Nitrogen adsorption analysis showed that the pore sizes of the supports got narrowed to 2.28 nm after deposition of sodalite and faujasite. The efficiencies of SOM and FAM membranes were evaluated by filtration tests of solutions containing methyl orange (MO) using a flow loop, which were developed for dead-end filtration. The retention of methylene orange (MO) followed the order: SOM > FAM > 160 µm ≤ Φ ≤ 250 µm clay support with 55%, 48% and 35%, respectively. Size exclusion was the predominant mechanism of filtration of MO through SOM, FAM, and the support. However, the charge repulsion between the surface of the membrane and the negatively charged MO have not been ruled out. The point of zero charge (pzc) of the clay support, SOM and FAM membrane were pHpzc = 9.4, pHpzc = 10.6, and pHpzc = 11.4, respectively. Filtrations of MO were carried out between pH = 5.5 and pH = 6.5, which indicated that the surface of the membranes was positively charged while MO was negatively charged. The interaction of MO with the membranes might have happened through its vertical geometry.

Organic Pollutants Photo-Degradation by Steady g-C3N4 Nanorods for Wastewater Treatment Applications

The photo-catalysis is a promising method for the degradation of harmful organic pollutants existing in the wastewater. In this research work, degradation of organic pollutants (dyes) have been done proficiently for the wastewater treatment applications. The synthesized steady graphitic carbon nitride (g-C3N4) nanorods have been examined by various sophisticated characterization techniques such as XRD, SEM, EDS, TEM, UV-Vis and PL. The hexagonal phase of g-C3N4 has been showed in XRD analysis. SEM shows that the morphology of g-C3N4 consists of aggregated nanorods. The EDS depicting only two peaks which are carbon and nitrogen and nitrogen without impurities. According to the study of UV-Visible and PL, 2.77 eV band gap has been observed showing consistency. The steady g-C3N4 nanorods have been used for the degradation of prominent organic dyes such as: methylene orange (MO), methylene blue (MB) and rhodamine-B (Rh-B) for treatment of wastewater which is a dire need. The effect of catalyst mass loading and time have been studied for this purpose. This research depicted that the anion (•O2−) and holes (h+) are attributed to the degradation of organic pollutants. whose Rh-B, MB and MO dyes. Research based a tentative photocatalytic mechanism has also been proposed for waste treatment purpose.

Functional Finishing of Polyester Fabric With Polystyrene-acrylic/zno Nanocomposite for Effective Dyes Filtration

Organic dyes such as Methyl Orange (MO) and Methylene Blue (MB) are widely used in different industries, becoming one of the leading emerging water contaminants. It is urgent to develop the most suitable materials for effective elimination of the dyes as they are non-biodegradable and are not removed efficiently by the traditional treatment methods. The present work applied polystyrene-acrylic/ZnO nanocomposite on the polyester surface by blade coating and one-bath pad methods. Features of surface chemical modifications were determined by FTIR, SEM analysis, WCA, N2 adsorption-desorption isotherms. The functionalised layer can create unprecedented function of filter textile material depending on the way of treatment. The possibility of using such fabrics as filters was explored for MO and MB in the concentration of 100 ppm. Water purification occurred by 60% from methylene blue and 40% from methylene orange flowing through the padded polyester filter and the covered polyester filter for 2 min, respectively. Moreover, it was shown that a colourless reduced form of MB – leuco-methylene blue (LMB) could be created. The functionalised layer of the developed filters through hydrogen bonding between the –OH groups of styrene-acrylic molecules and the –N(CH3)2 groups on LMB can stabilise LMB.

pH Dependent Synthesis And Characterization of Bismuth Molybdate Nanostructure for Photocatalysis Degradation of Organic Pollutants

Bismuth Molybdate nanostructures were synthesized using a simple hydrothermal method at varied pH (2,4,6,8, and 10) for 15 h at 180°. The results show that the pH precursor solutions have a significant impact on the morphology, phase formations and photocatalytic activity. The FESEM observations and XRD analysis, at low PH level, Bi2MoO6 nanoplates have formed while gradually convert to Bi2MoO6 spherical nanoparticle at high PH level. The optical absorption study demonstrated that Bi2MoO6 nanoplates absorbed visible light, but that there was a blue shift when compared to the cubic Bi4MoO9 structures. Photocatalytic activity revealed that nanoplates in pH = 4 sample has excellent photocatalytic activity for degradation of rhodamine (RhB), methylene orange (MO) and phenol under visible- light irradiation (λ > 400 nm). The most important point is photodegradation 90% of phenol within 300 min.

Removal of organic dye compounds in water and wastewater samples based on covalent organic frameworks -titanium dioxide before analysis by UV-VIS spectroscopy

A simple and rapid microwave-assisted combustion method was developed to synthesize homogenous carbon nanostructures (HCNS). This research presents a new and novel nanocomposite structures for removal of methylene red (2-(4- Dimethylaminophenylazo)benzoic acid), methylene orange (4-[4-(Dimethylamino)phenylazo]benzenesulfonic acid sodium salt) and methylene blue (3,7-bis(Dimethylamino)phenazathionium chloride)with semi degradation-adsorption solid phase extraction (SDA-SPE) procedure before determination by UV-VIS spectroscopy. A covalent organic frameworks (COFs) with high purity were synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the self-assembled carbon nanostructures (COFs) synthesized with the cost-effective method which was used as a novel adsorbent for adsorption of dyes after semi-degradation of methylene red, orange and blue (1-5 mg L-1) as an organic dye by titanium dioxide (TiO2) nanoparticales in presence of UV radiation. Based on results, the COFs/TiO2 has good agreement with the Langmuir adsorption isotherm model with favorite coefficient of determination (R2= 0.9989). The recovery of dye removal based on semi-degradation/adsorption of COFs/TiO2 and adsorption of COFs were obtained 98.7% and 48.3%, respectively (RSD less than 5%). The method was validated by spiking dye to real samples.

Network structure-based decorated CPA@CuO hybrid nanocomposite for methyl orange environmental remediation

A unique network core–shell hybrid design-based cross-linked polyaniline (CPA), which was coated with CuO nanoparticles (NPs) and decorated with nitrogen-doped SWCNT/GO/cellulose N-SWCNTS-GO-CE, has been fabricated using the oxidative polymerization technique. This hybrid nanocomposite shows excellent photocatalytic degradation and an acceptable adsorption capability for Methyl Orange (MO) dye in aqueous solutions with a very slight effect for the N-SWCNTS-GO-CE CuO component. The prepared nanocomposites were used for the removal of a carcinogenic and noxious dye, Methyl Orange, from aqueous samples under various adsorption conditions. Approximately 100% degradation of 10 mg/L of Methylene orange dye was observed within 100 min at pH 6.0 using 50 mg/L CPA/N-SWCNTS-GO-CE/CuO nanocomposite under UV radiation. Additionally, significant factors were investigated on the degradation process including the contact time, MO initial concentration (Ci), solution pH, and dosage of the CuO nanocomposite. All investigated experiments were performed under UV radiation, which provided significant data for the MO degradation process. Furthermore, the recovery of the nanocomposite was studied based on the photocatalytic process efficiency. The obtained data provide the high opportunity of reusing CPA/N-SWCNTS-GO-CE/CuO nanocomposite for numerous photocatalytic processes. The CPA/N-SWCNTS-GO-CE/CuO nanocomposite was prepared via chemical oxidative copolymerization of polyaniline (PANI) with p-phenylenediamine (PPDA) and triphenylamine (TPA) in the presence of N-SWCNTS-GO-CE and CuO NPs. The morphology, structure and thermal properties of the CPA/N-SWCNTS-GO-CE/CuO nanocomposite were investigated using various techniques, including FTIR, XRD, RAMAN, SEM, MAP, EDX, TEM, TGA and DTG. Therefore, CPA/N-SWCNTS-GO-CE/CuO nanocomposite can be effectively used as a convenient and reusable adsorbent to remove hazardous dye from wastewater.

A new core–shell Z-scheme heterojunction structured La(OH)3@In2S3 composite with superior photocatalytic performance

Constructing Z-scheme heterojunction photocatalyst with strong redox ability to make for enhanced photocatalytic performance and efficient charge separation is extremely attractive but still underdeveloped. Herein, a Z-scheme heterojunction structured La(OH)3@In2S3 composite (labeled by “LIS”) with photocatalytic for the methylene orange (MO) degradation under simulated light irradiation has been developed. The as-prepared LIS, together with commercial La(OH)3 and pure In2S3 fabricated with the identical processing method and starting materials as those of LIS, was characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra and electrochemical impedance spectroscopy. The results show the heterojunction of La(OH)3/In2S3 has prolonged the lifetime of the photo-generated carriers. The photocatalytic activity test shows that over only a small amount (0.02 g in 100 ml MO) of LIS, the photodegradation rate of 95% toward MO can be obtained in 90 min, which is about 3.4 times higher than that over pure In2S3. The active species trapping experiments indicate that there were four active species playing roles in photodegradation as the following order: e– = ∙OH < h+ < ∙O2–. A mechanism of Z-scheme heterojunction was proposed and well explained the enhanced photocatalytic performance. This work provides a new cost-effective photocatalyst with high photocatalytic properties.