Highly Efficient Elimination of Pb+2 and Al+3 Metal Ions from Wastewater Using Graphene Oxide/3,5-Diaminobenzoic Acid Composites: Selective Removal of Pb2+ from Real Industrial Wastewater.

In this study, graphene oxide (GO) was functionalized with 3,5-diaminobenzoic acid (DABA) by a one-step method to produce functionalized graphene oxide (FGO). FGO is a new type of absorbent crystalline substance that has a high surface area and a large porosity site as well as a large number of dentate functional groups which lead to enhanced adsorption performance for heavy metal ions. The adsorption efficiency of FGO for Pb+2 and Al+3 metal ions was extra satisfactory when compared with GO due to the ease of design and the homogeneous structure of FGO. The structure of synthesized GO and FGO was confirmed by different techniques such as FTIR, XRD, TGA, BET nitrogen adsorption-desorption methods, and TEM analyses. The mass of utilized adsorbents, the pH of the medium, the concentration of ionic species in the medium, temperature, and process time were all investigated as variables in the adsorbent procedure. The experimental data recorded that the maximum adsorption efficiency of the 0.5 g/L FGO composite was 99.7 and 99.8% for Pb+2 and Al+3 metal ions, respectively, while in the case of using GO, the maximum adsorption efficiency was 92.6 and 91.9% at ambient temperature in a semineutral medium at pH 6 after 4 h. The adsorption results were in good conformity with the Freundlich model and pseudo-second-order kinetics for Pb+2 and Al+3 metal ions. Also, the reusability study indicates that FGO can be used repeatedly at least for five cycles with a slight significant loss in its efficiency.

Growth Inhibition of Sulfate-Reducing Bacteria during Gas and Oil Production Using Novel Schiff Base Diquaternary Biocides: Synthesis, Antimicrobial, and Toxicological Assessment.

Upstream crude oil production equipment is always exposed to destruction damagingly which is caused by sulfate-reducing bacterium (SRB) activities that produce H2S gas, which leads to increased metal corrosion (bio-fouling) rates and inflicts effective infrastructure damage. Hence, oil and gas reservoirs must be injected with biocides and inhibitors which still offer the foremost protection against harmful microbial activity. However, because of the economic and environmental risks associated with biocides, the oil and gas sectors improve better methods for their usage. This work describes the synthesis and evaluation of the biological activities as the cytotoxicity and antimicrobial properties of a series of diquaternary cationic biocides that were studied during the inhibition of microbial biofilms. The prepared diquaternary compound was synthesized by coupling vanillin and 4-aminoantipyrene to achieve the corresponding Schiff base, followed by a quaternization reaction using 1,6-bromohexane, 1,8-bromooctane, and 1,12-bromododecane. The increase of their alkyl chain length from 6 to 12 methylene groups increased the obtained antimicrobial activity and cytotoxicity. Antimicrobial efficacies of Q1-3 against various biofilm-forming microorganisms, including bacteria and fungi, were examined utilizing the diameter of inhibition zone procedures. The results revealed that cytotoxic efficacies of Q1-3 were significantly associated mainly with maximum surface excess and interfacial characteristics. The cytotoxic efficiencies of Q1-3 biocides demonstrated promising results due to their comparatively higher efficacies against SRB. Q3 exhibited the highest cytotoxic biocide against the gram +ve, gram -ve, and SRB species according to the inhibition zone diameter test. The toxicity of the studied microorganisms depended on the nature and type of the target microorganism and the hydrophobicity of the biocide molecules. Cytotoxicity assessment and antimicrobial activity displayed increased activity by the increase in their alkyl chain length.

Effect of Reaction Parameters on Catalytic Pyrolysis of Waste Cooking Oil for Production of Sustainable Biodiesel and Biojet by Functionalized Montmorillonite/Chitosan Nanocomposites.

The use of waste oils as pyrolysis feedstocks to manufacture high-grade biofuels has prompted researchers to focus on developing renewable energy to overcome the depletion of fossil fuel supplies and the global warming phenomena. Because of their high hydrogen and volatile matter concentration, waste oils are ideal raw materials for the production of biofuels. It is challenging to attain satisfactory results with conventional methods, such as transesterification, gasification, solvent extraction, and hydrotreating due to flaws such as high energy demand, long time, and high operating costs. Catalytic pyrolysis of waste edible oils was employed as a resource for the generation of biodiesel. The application of the catalytic cracking process has the potential to alleviate the existing situation. In this study of catalytic cracking conversion of waste cooking oil to produce different biofuels, grades were investigated using two heterogeneous catalysts. The catalysts were activated montmorillonite (PAMMT) clay and its modified form using a chitosan biopolymer (PAMMT-CH) nanocomposite. The catalysts were identified using infrared spectroscopy, X-ray diffraction patterns, transmittance electron microscopy images, surface area, and thermal stability. The catalysts were tested for their performances using different amounts (0.1-1% by weight) at a temperature assortment of 200-400 °C during a time range of 60-300 min. The experimental studies were carried out in a batch reactor. GC mass spectra were used to investigate the catalytic cracking products. Fractional distillation is used to separate the final products from various reaction conditions. The physicochemical properties of resulting biofuels were profiled by quantifying their densities, viscosities, specific gravities, pour points, flash and fire points, cetane numbers, carbon and ash residues, and sulfur contents. The optimum conditions of the yield product were 300 and 400 °C, catalyst weights of 0.7 and 0.8% w/v, and reaction times of 120 and 180 min concerning the (PAMMT) and (PAMMT-CH) nanocomposite, respectively. The determined properties were located within the limits of the specific standards of ASTM specifications. As a result, the PAMMT nanocomposite produced biofuel comparable to biodiesel according to ASTM specifications, while the PAMMT-CH nanocomposite produced biofuel comparable to biojet.

Electrochemically Induced Mesomorphism Switching in a Chlorpromazine Hydrochloride Lyotropic Liquid Crystal.

The discovery of electrochemical switching of the Lα phase of chlorpromazine hydrochloride in water is reported. The phase is characterized using polarizing microscopy, X-ray scattering, rheological measurements, and microelectrode voltammetry. Fast, heterogeneous oxidation of the lyotropic liquid crystal is shown to cause a phase change resulting from the disordering of the structural order in a stepwise process. The underlying molecular dynamics is considered to be a cooperative effect of both increasing electrostatic interactions and an unfolding of the monomers from "butterfly"-shaped in the reduced form to planar in the oxidized form.