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The adverse environmental effects of petroleum-based packaging plastics have necessitated the need for eco-friendly bioplastics. Most bioplastics are starch-based and are not without drawbacks, hence there is the need for their properties to be improved. In this study, the effect of varying concentrations of dialdehyde starch and silica solutions on the physical, mechanical, biodegradable, surface topology, and thermal properties of the bioplastic films was examined. The additive concentrations were varied from 60 to 100%. The bioplastic films produced with dialdehyde starch solution recorded better moisture content (6.62–11.85%), bioplastic film solubility (4.23–7.90%), and tensile strength (1.63–3.06 MPa), against (11.24–14.26%), (7.77–19.27%) and (0.53–0.73 MPa) respectively for bioplastic films produced with silica solution. The atomic force microscopy analysis; root-mean-square roughness, kurtosis, and skewness revealed better miscibility and compatibility between the starch matrix and the dialdehyde solution than between the starch matrix and the silica solution. Bioplastic with added dialdehyde starch solution has better tensile strength and long biodegradability than that with silica solution. The research has demonstrated that bioplastic film produced with starch and dialdehyde starch solution has better properties than the one produced with starch and silica solution. The properties evaluation results of the bioplastic films thus demonstrated their aptness for food packaging applications. Graphic abstract

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The need for a broad spectrum antimicrobial mouthwash is highly desirable to reduce, control and prevent various types of dental diseases. Hence, research into the production of herbal toothpaste to suppress the incidence of dental diseases is pertinent. The present study formulated herbal toothpastes from edible and medicinal plants namely; Syzygium aromaticum , Dennettia tripetala , and Jatropha curcas latex. The antimicrobial activity of the toothpastes was assessed against some oral pathogenic microorganisms using agar well diffusion. Phytochemical analysis of S. aromaticum and D. tripetala revealed the presence of phenols, flavonoids, alkaloid, and saponins. The major constituent of the plants from gas chromatography mass spectrometer (GC/MS) analysis are eugenol (83.58%), caryophyllene (4.35%) and phenol, 2-methoxy-4-(2-propenyl)-, acetate (12.07%) from S. aromaticum, while D. tripetala had glutaric acid (57.57%), eugenol (2.9%), caryophyllene (1.12%), and 1,6,10-dodecatrien-3-ol, 3,7,11-trimethyl-,(E)- (3.36%). The pH and specific gravity of the formulated toothpastes respectively ranged from 8.57 to 9.67 and 1.08 to 1.10, while the pH and specific gravity of commercial toothpastes were from 5.39 to 8.55 and 0.97 to 1. 11 respectively. The formulated toothpastes have better and significant (P < 0.05) antimicrobial effect when compared to commercial toothpastes. The zones of inhibition of formulated toothpastes against the tested microorganisms ranged from 4.0 to 18.30 mm, while MIC ranged from 2.5 to 20.0 mg/mL. The formulated toothpastes exhibited potent antimicrobial property against the tested pathogens as a result of bioactive compounds in them. Hence, these biomolecules can be extracted for the production of safe and effective herbal-based toothpaste. Electronic supplementary material The online version of this article (10.1186/s13568-019-0744-2) contains supplementary material, which is available to authorized users.

Effect of the dispersion method employed during the synthesis of carbon nanotube (CNT)/polysulfone-infused composite membranes on the quality and separation performance of the membranes during oil–water mixture separation is demonstrated. Carbon nanotube/polysulfone composite membranes containing 5% CNT and pure polysulfone membrane (with 0% CNT) were synthesized using phase inversion. Three CNT dispersion methods referred to as Method 1 (M1), Method 2 (M2), and Method 3 (M3) were used to disperse the CNTs. Morphology and surface property of the synthesized membranes were checked with scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, respectively. Separation performance of the membranes was evaluated by applying the membrane to the separation of oil–water emulsion using a cross-flow filtration setup. The functional groups obtained from the FTIR spectra for the membranes and the CNTs included carboxylic acid groups (O–H) and carbonyl group (C=O) which are responsible for the hydrophilic properties of the membranes. The contact angles for the membranes obtained from Method 1, Method 2, and Method 3 were 76.6° ± 5.0°, 77.9° ± 1.3°, and 77.3° ± 4.5°, respectively, and 88.1° ± 2.1° was obtained for the pure polysulfone membrane. The oil rejection (OR) for the synthesized composite membranes from Method 1, Method 2, and Method 3 were 48.71%, 65.86%, and 99.88%, respectively, indicating that Method 3 resulted in membrane of the best quality and separation performance.

Microcrystalline cellulose was prepared from wastes of Tithonia diversifolia, inflorescence stems of Musa sapientum, and Musa paradisiaca by soda-anthraquinone-ethanol pulping method. They were bleached by sodium chlorite and then alpha-cellulose was isolated, followed by preparation of microcrystalline cellulose. The study revealed the effect of various processing stages on the properties of the cellulose obtained. Yields of more than 80% of microcrystalline cellulose were obtained. Fourier transform infrared (FTIR) and solid state 13 C Nuclear magnetic resonance ( 13 C NMR) confirmed the presence of the major expected peaks in microcrystalline cellulose. Scanning electron microscopy (SEM) revealed that Musa species had short fiber length and mixtures of non-aggregated spherical, rod-shaped and thread like microcrystalline cellulose, but Tithonia diversifolia had aggregate crystal packed formation. The results compared well with those of other authors and were able to meet most of the requirements specified in British Pharmacopoeia. The study revealed that a drug excipient like microcrystalline cellulose that could protect thermo-labile active ingredients could be successfully obtained from abundant non-woody agricultural wastes.

Ethylene diaminetetraacetic acid (EDTA) functionalized graphene was synthesized from Nigerian coal using a chemical exfoliation method and the graphene was applied for the removal of Congo red dye from aqueous solutions.The synthesized coal graphene and the raw coal were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, Scanning electron microscopy and Energy (SEM)-Energy dispersive X-ray (EDX) spectroscopy. The SEM data revealed surface roughness which is enhanced in the prepared graphene while the EDX revealed an increase in carbon, the main constituent of graphene, from about 26% in the raw coal to about 80% in the prepared graphene. Various adsorption parameters, such as pH, contact time, concentration of Congo red and temperature, were varied for the removal of the dye using raw coal and the synthesized coal graphene. The Liu isotherm gave the best fit of the equilibrium data than the Langmuir, Freundlich and Dubinin-Radushkevich models. The maximum adsorption capacities of the raw coal and synthesized coal graphene at 25 °C are 109.1 mg/g and 129.0 mg/g, respectively. The Avrami fractional order kinetic model was the best model for description of the kinetic data. The model had the lowest values of standard deviation than the pseudo-first order and pseudo-second order models. The adsorption process of the two materials occurred via two stages as proved by intraparticle diffusion model. The adsorption process of the Congo red removal was spontaneous, feasible and endothermic. The study conclusively revealed the graphene nanomaterial to be a viable adsorbent for textile wastewater treatment.

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