Extraction and characterization of alumina nanopowders from aluminum dross by acid dissolution process

A significant amount of aluminum dross is available as a waste in foundry industries in Bangladesh. In this study, alumina was ex- tracted from aluminum dross collected from two foundry industries situated in Dhamrai and Manikgang, near the capital city, Dhaka. Alu- minum dross samples were found to approximately contain 75wt% A1203 and 12wt% SIO2. An acid dissolution process was used to recover the alumina value from the dross. The effects of various parameters, e.g., temperature, acid concentration, and leaching time, on the extrac- tion of alumina were studied to optimize the dissolution process. First, AI（OH）3 was produced in the form of a gel. Calcination of the AI（OH）3 gel at 1000℃, 1200℃, and 1400℃ for 2 h produced O-AlcOa, （t~＋O）-A1203, and u-alumina powder, respectively. Thermal charac- terization of the AI（OH）3 gel was performed by thermogravimetric/differential thermal analysis （TG/DTA） and differential scanning calo- rimetry （DSC）. The phases and crystallite size of the alumina were determined by X-ray diffraction analysis. The dimensions of the alumina were found to be on the nano level. The chemical compositions of the aluminum dross and alumina were determined by X-ray fluorescence （XRF） spectroscopy. The microstructure and morphology of the alumina were studied with scanning electron microscopy. The purity of the alumina extracted in this study was found to be 99.0%. Thus, it is expected that the obtained alumina powders can be potentially utilized as biomaterials.

Anti-inflammatory and antioxidant activities of ethanolic extract of aerial parts of Vernonia patula(Dryand.)Merr.

Objective:To investigate the inflammatory and antioxidant activities of ethanolie extract of aerial part of Vernonia patula(Dryand.)Merr(EAV).Methods:The anti-inflammatory activity of EAV was studied using carrageenan and histamine-induced rat paw edema test at different doses(100.200 and 400 mg/kg body weight).DPPH free radical scavenging,nitric oxide scavenging,reducing power and Fe^(2+)ion chelating ability were used for determining antioxidant activities.Results:The EAV,at the dose of 400 mg/kg,showed a significant anti-inflammatory activity(P<0.01)both in the carrageenan and histamine-induced oedema test models in rats,showing62.86%and 64.42%reduction in the paw volume comparable to that produced by the standard drug indomethacin(67.26%and 66.01%)at 5 h respectively.In DPPH free radical scavenging test,IC_(50)value for EAV was found fairly significant 36.59μg/mL when compared to the IC_(50)value of the reference standards ascorbic acid 8.97μg/mL.The IC_(50)values of the extract and ascorbic acid were 47.72 and 12.39μg/mL,respectively in nitric oxide scavenging assay.The IC_(50)value of the EAV(33.59μg/mL)as percentage of Fe^(2+)ion chelating ability was also found significant compared to that of EDTA(9.16μg/mL).The maximum absorbance for reducing power assay was found to be1.928 at 100μg/mL when compared to 2.449 for standard ascorbic acid.The total phenolic content was 198.81 mg/g of gallic acid equivalent.Acute toxicity test showed that the plant might be safe for pharmacological uses up to a dose level of 3200 mg/kg of body weight in rats.Conclusions:Therefore,the obtained results suggest the acute anti-inflammatory and antioxidant activities of the EAV and thus provide the scientific basis for the traditional uses of this plant part as a remedy for inflammations.

ALKALINE PULP OF CORN STALKS

Pulping of corn stalks was studied in soda, soda-anthraquinone (AQ), kraft and kraft-AQ processes. The time, temperature and alkali concentration were varied in soda process. In respect to kappa number and pulp yield, 1 hour cooking at 1400C in 14% alkali were best conditions for corn stalks pulping. Pulp yield was increased by 5.5% and kappa number was reduced by 4.4 points with an addition of 0.05% AQ in the soda liquor. Breaking length was better in soda-AQ process than soda process but tear strength was inferior. In the kraft process, pulp yield was increased with increasing sulphidity and decreasing active alkali. The effectiveness of AQ in the low and high sulphidity kraft process was studied. Results showed that AQ was more effective in low sulphidity than high sulphidity. Strength properties in kraft processes were better than the soda and soda-AQ processes.

Development of the N-Doped Cu-Carbon Composite as a Novel Catalyst for the Removal Reactive Black 5

In this study, two Cu-based catalysts with and without N doped carbon matrix, named N-Cu/CuO/C and Cu/CuO were synthesized via calcination of melamine-cupper acetate complex and cupper acetate at 500°C under an inert atmosphere. The catalysts were characterized by X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and CHNS elemental analyzer. The catalytic activity of both catalysts was evaluated through the NaBH4 associated reduction of commercial textile dye named reactive black 5 (RB5). The kinetics of the reduction of reactive black 5 was also described by the pseudo-first-order kinetic equation. For the studied reduction, N-Cu/CuO/C exhibited enhanced catalytic activity both in conversion and kinetics (97% conv. in 315 sec) compared to that of by Cu/CuO/C (25% conv. in 1500 sec). Besides, N-Cu/CuO/C also demonstrated good reusability up to four consecutive cycles.

Investigation of the Surface Morphology and Structural Characterization of Palm Fiber Reinforced Acrylonitrile Butadiene Styrene (PF-ABS) Composites

With the aid of Injection Moulding Machine (IMM) Palm fiber reinforced Acrylonitrile Butadiene Styrene (ABS) composites (PF-ABS) were prepared. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) experiments were performed to study the surface morphology, microstructure (if it crystalline or noncrystalline) and new bond formation after preparation of the composites. SEM pattern shows that after addition of palm fiber in PF-ABS composites the brittleness increased due to creation of voids in the composites except 10% fiber content in PF-ABS. From XRD pattern it is clear that the palm fiber, ABS and PF-ABS composites are amorphous in nature. Moreover FTIR spectrum shows that there is no new bond formed after addition of palm fiber in ABS polymeric matrix to create PF-ABS composites.

Nutritional quality and safety aspects of wild vegetables consume in Bangladesh

Objective: To evaluate the nutritional composition, including major minerals, essential trace elements and toxic heavy metals of five different wild vegetables Dhekishak(Dryopteris filix-mas), Helencha(Enhydra fluctuans), Kalmishak(Ipomoea aquatica),Patshak(Corchorus capsularis) and Shapla stem(Nymphaea stellata) and their safety aspects.Methods: Proximate parameters moisture, ash, fat, fiber, protein, carbohydrate and energy; major minerals Na, K, Ca and Mg; trace elements Fe, Zn and Cu; and toxic heavy metals Pb, Cd, Cr, Ni and Hg were evaluated in the selected wild vegetables using the standard food analysis techniques.Results: The results from nutritional analysis showed that all the wild vegetables used in this study had a low content of crude fat and high content of moisture, ash, crude protein,crude fiber, carbohydrate and energy having the recommended dietary allowances. The vegetables were also rich in major minerals Na, K, Ca and Mg, sufficient in essential trace elements Fe, Cu and Zn while the heavy metals Pb, Cr and Ni were detected higher in amount in all the vegetables except Patshak than the limits recommended by Food and Agriculture Organization/World Health Organization. The heavy metals Cd and Hg were not detected in any vegetable.Conclusions: The outcome of this study suggests that the wild vegetables have very good nutritional potential to meet the recommended dietary allowances, but special awareness should be taken for public health concern about the high level of Pb, Cr and Ni which exceed the Food and Agriculture Organization/World Health Organization recommended limits for the metals in vegetables.

Cytotoxic, Antimicrobial and Antioxidant Properties of <i>Commelina diffusa</i>Burm. F.

Commelina diffusa Burm. F. is a herbaceous tropical plant with different traditional medicinal uses. Present study is aimed to isolate the bioactive compounds from DCM-Methanol extract of the powdered whole plant of Commelina diffusa and to investigate the cytotoxic, antimicrobial and antioxidant activities of the crude extract and its twelve vacuum liquid chromatographic fraction (CD1-12). Vacuum Liquid Chromatography (VLC) was employed to isolate bioactive metabolites. The physicochemical properties of the isolated compound were examined and the molecular structure was elucidated by NMR spectroscopy.?Cytotoxic, antibacterial, antioxidant activities were evaluated following brine shrimp lethality bioassay, disc diffusion method and DPPH free radical scavenging assay respectively. The isolated compound was identified as steroid (stigmasterol) which had significant cytotoxic effect on vero cell line. The crude extract and its fractions (CD8-CD12) exhibited strong cytotoxicity in brine shrimp lethality bioassay having LC50 values 3.79, 9.19, 29.49, 16.60, 19.36, 44.58 μg/mL respectively. The crude extract showed mild to strong antibacterial activity. Fractions (CD5-CD12) showed mild to strong antibacterial activity against Escherichia coli in comparison with Kanamycin (standard). Strong antioxidant activities were found in crude extract (IC50 value 30.52 μg/ml), CD11 (IC50 value 39.27 μg/ml) and CD12 (IC50 value 19.50 μg/ml). The study suggests Commelina diffusa plant extract to have strong antioxidant and cytotoxic activity which is indicative of presence of compounds with broad spectrum of curative applications. One compound namely stigmasterol has been isolated from the plant.

A Review on Ethnomedicinal, Pharmacological, Phytochemical and Pharmaceutical Profile of Lady’s Finger (<i>Abelmoschus esculentus</i>L.) Plant

Abelmoschus is a genus of about fifteen species belongs to the family Malvaceae. The herb, popularly known as Lady’s Finger or Okra (in English) is a nutritional source used for both medicinal and culinary purposes. The plant is widely distributed from Africa to Asia, Southern Europe, and America. This comprehensive account provides a botanical description of the plant, its phytochemical constituents and pharmacological activities focusing anti-diabetic, anti-oxidant, anti-adhesive, gastro-protective, hepatoprotective, and immunomodulating actions. Most of the pharmacological effects can be explained by the constituents like tannins, terpenoids, flavonoids and glycosides present in all plant parts. However, future efforts should concentrate more on in vitro and in vivo studies and also on clinical trials in order to confirm traditional wisdom in the light of a rational phytotherapy. The present review is an overview of phytochemistry and ethnopharmacological studies that support many of the traditional?ethnomedicinal uses of the plant.

Comparative Study between the Effect of <i>Momordica charantia</i>(Wild Type) Fruits and <i>Coccinia cordifolia</i>’s Leaf on Hypoglycemic and Hypolipidemic Activities of Alloxan

Aims: The study was aimed to compare the hypoglycemic and hypolipidemic effect of Momordica charantia (wild type) fruits and Coccinia cordifolia’s leaf in alloxan induced type 2 diabetic Long-Evans rats. Methods: All rats were divided into groups A to H (n = 48, 06 rats per group). They were made diabetic by intraperitoneally injecting alloxan monohydrate 150-mg/Kg-body weight. Groups A and B were provided with normal diet and glibenclamide plus normal diet respectively. C to H groups were provided with different percentages (70%, 50% and 30% of regular diet) of samples. Different biochemical parameters (blood glucose level, serum total cholesterol, triglyceride (TG), LDL, HDL, serum insulin, hepatic glycogen) were observed for 21 consecutive days (at eight days interval). Results: Oral administration of both of the Momordica charantia (wild type) fruits and Coccinia cordifolia’s leaf significantly (p nificantly (p level and LDL in type 2 diabetic rats. HDL levels were increased slightly and hepatic glycogen level was more or less unchanged in both groups at 22nd day. Conclusion: Though both samples show hypoglycemic and hypolipidemic activities, 50% wild type fruits of Momordica charantia were more significant

Isolation, Identification and Pharmacological Activities of Endophytic Fungi from <i>Aponogeton undulatus</i>Roxb.

The objective of this study is to isolate, identify and investigate the pharmacological activities of the endophytic fungi from an aquatic plant Aponogeton undulatus Roxb. (A. undulatus). Endophytic fungi were isolated and identified based on morphological characters. The molecular identification of the fungal isolates was performed using by analyzing the DNA sequence based on mega BLAST program. Spectrums of antibacterial and antifungal activities were studied by Agar diffusion methods. Extracts of the endophytic fungal strains isolated from the plant A. undulatus were screened for probable cytotoxic activities using brine shrimp lethality bioassay. Six endophytic fungi, namely AULE-1, AULE-2, AULE-3, AURE-1, AURE-3 and AURE-4 were isolated and purified from the leaves and roots of the plant such as strains AULE-1 as Trichooderma sp., AULE-2 as Carvularia sp. AULE-3 as Penicillium sp. strains AURE-1 and AURE-4 as Fusarium sp. and AURE-3 as Mucor sp. Strain AURE-4 was further identified as Fusarium solani. At 300 μg/disc concentration, six ethyl acetate extracts of endophytic fungi of the plant A. undulates showed moderate to significant activities against most of the test bacteria and pathogenic fungi. The strain AURE-4 exhibited strong cytotoxic activities (10.18 μg/mL) compared to the standard antitumor agent vincristine sulphate and this positive result suggests that fungal extracts may contain antitumor or pesticidal compounds. This is the first study to report the isolation, identification, antimicrobial and cytotoxic properties of endophytic fungi of Aponogeton undulatus Roxb. in Bangladesh.

Isolation of Bulk Amount of Piperine as Active Pharmaceutical Ingredient (API) from Black Pepper and White Pepper (<i>Piper nigrum</i>L.)

In the pharmaceutical world the majority of the active pharmaceutical ingredients (API) have been obtained from the natural products. Piperine is such naturally occurring alkaloid which can be considered as major bioactive phytochemical having broad spectrum of pharmacological activities. It is obtained from the most valuable ethnomedicinal spices peppercorns i.e. black pepper and white pepper, which are the fruits of the Asian vine Piper nigrum L. Because of the widespread traditional uses of this medicinal compound, present article reveals a simple and effective isolation method of bulk piperine. The novelty of this investigation is to provide an idea for utilizing such natural method of large scale commercial piperine production as API drug in spite of chemical synthesis. Piperine was isolated in a pure crystal form and characterized by its melting point, X-Ray diffraction (XRD) studies and spectral data, including two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Chromatographic techniques like Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) were applied to determine the purity of the yielded piperine. It was found that piperine yield from black pepper was within 2.5% - 3.0% and from white pepper within 4.0% - 4.5% and the purity of the yielded piperine was found to be up to 98.5% for black pepper and 98.2% for white pepper. Considering this yield value and purity it is indicated that, such effective isolation method can be successfully utilized for industrial large-scale production commercially. According to the result, it can be claimed that, as a natural product the isolated piperine can also be utilized as API drug like other expensive chemically synthesized piperine in different drug formulation.

Influence of Ni substitution on structural,morphological,dielectric,magnetic and optical properties of Cu-Zn ferrite by double sintering sol–gel technique

Polycrystalline NiCuZn ferrite(Ni_(x)Cu_(0.3)Zn(0.7-x)Fe_(2)O_(4);x=0.2,0.3,0.4 and 0.5)were prepared through solgel auto combustion method applying double sintering technique.Structural,morphological,elemental analyses(EDS),Fourier-transform infrared spectroscopy(FTIR),Direct Current(DC)electrical resistivity,dielectric,magnetic and optical properties of prepared samples were analyzed.XRD profiles reveal the formation of simple cubic spinel structure without any traceable impurity.The average crystallite size lies within the range of 22–29 nm.Lattice parameter decreases with increasing Ni concentration.Room temperature DC resistivity was recorded from 6:39×10^(5)to 3:79×10^(5)Ωcm.Both dielectric constant(ε)and loss factor(tanδ)were decreased with increase of frequency while AC conductivity increases.FTIR absorption peak occurred at three different frequency ranges at 570-577 cm^(-1),1635-1662 cm^(-1)and 3439–3448 cm^(-1).Magnetic properties were investigated by using vibrating sample magnetometer(VSM).Decreasing trends were observed for saturation magnetization(Ms),magnetic coercivity(Hc)and remanant magnetization(Mr)with the increase of Ni content.Optical band gap(-2.70-2.79 eV)were calculated from diffuse reflectance data by using Kubelka–Munk function.

Development of chemometric model for characterization of non-wood by FT-NIR data

In this study,a model for prediction of lignocellulose components of agricultural residues has been developed with Fourier Transformed Near Infrared(FT-NIR)spectroscopy data.Two calibration techniques(Principal Component Regression(PCR)and Partial Least Square Regression(PLSR))were assessed for prediction of lignin,holocellulose,α-cellulose,pentosan and ash,and found the PLSR better for lignin,holocellulose andα-cellulose.The PCR also produced better results for quantification of pentosan and ash.Spectral range(7000-5000 cm^(-1))showed more informative than other parts of the spectral data.The PLSR showed maximum value of R^(2)(R^(2)=0.91%)for prediction of holocellulose.For the prediction of pentosan,the PCR was better(R^(2)=0.68%).The PCR also showed better results(R^(2)=86%)for quantification of ash.To determine amount of lignin,the PLSR was the best(R^(2)=0.83%)when the spectral data were de-trained and smoothed with Savitzky-Golay(S-G)filtering simultaneously.For prediction ofα-cellulose,the PLSR was the best model(R^(2)=0.94%)when the data were pretreated with mean normalization.Considering the best alternatives inNear Infrared(NIR)data preprocessing and calibration techniques,methods for quantification of lignocellulose components of agricultural residues have been developed which is rapid,cost effective,and less chemical intensive and easily usable in pulp and paper industries and pulp testing laboratories.

Synthesis,structural investigation,dielectric and magnetic properties of Zn^(2+)-doped cobalt ferrite by the sol-gel technique

Zinc substituted cobalt ferrite nanoparticles with elemental composition Co_(1-x)Zn_(x)Fe_(2)O_(4)(x=0.0,0.2,0.4,0.6)were prepared by the sol-gel auto-combustion technique using Co,Fe,Zn nitrate as a precursor where nitrates to citrate was 1:3.The as prepared powder of cobalt zinc ferrite was sintered at 900○C for 3 h.Structural,morphological,dielectric and magnetic properties were studied by x-ray diffractometer(XRD),scanning electron microscope(SEM),high precision impedance analyzer and vibrating sample magnetometer(VSM),respectively.The peaks obtained from the XRD confirmed samples having crystallite(32–36 nm)single phase inverse spinel structure without any traceable impurity.Lattice parameters were calculated from XRD and it increases with Zn content.SEM revealed irregularly shaped grains(-0.5–0.7μm)morphology with heterogeneous distribution.The dielectric constant(ε′)and dielectric loss(tanδ),have been measured as a function of frequency at room temperature.The dependence of ε′ and tan δ with frequency showed the normal dielectric behavior in accordance with the Maxwell-Wagner type of interfacial polarization and electron hopping change between Co^(2+)and Co^(3+)as well as between Fe^(2+)and Fe^(3+)ions at octahedral sites.

Soda pulping of umbrella palm grass (cyperus flabettiformic)

Chemical,morphological and anatomical characteristics of Cyperus flabettiformic were evaluated.It is characterized with lowα-cellulose(32.2%)and moderate lignin(24.0%)content.Fiber length of C.flabettiformic was shorter(0.94mm)but slender ratio was extremely high(166).Anatomically,this grass is constituted by homogeneous parenchyma cells and the vascular bundles(11.8%).Delignification of C.flabettiformic was carried out by conventional soda pulping under varying alkali charge,time and liquor to material ratio at the boiling temperature.Total pulp yield was 55.0%with kappa number 15.5 at the cooking conditions of 12%alkali charge,2 h of cooking and liquor to material ratio 10:1.Multivariate data analysis was used to evaluate the influence of alkali charge,cooking time and liquor ratio on pulp yield and kappa number.Alkali charge had a significant effect on pulp yield and kappa number.PLSR model showed better prediction efficiencies for pulp yield and PCR model performed better prediction for kappa number.Initial drainage resistance and papermaking properties of C.flabettiformic pulp were higher than other nonwood.

Variation of chemical characteristics and pulpability of dhaincha(Sesbania bispinosa)on location

Dhaincha(Sesbania bispinosa(Jacq.)Wight)is a crop generally cultivated for improving soil quality.Due to the lack of forest worldwide,alternative source of raw materials for cellulose industries is the main concern today.In this investigation,dhaincha samples of 21 accessions were collected from different districts of Bangladesh in order to study the variation of chemical characteristics and its pulpability.The lignin,pentosan andα-cellulose content were varied from 21 to 23%,16 to 18%and 38 to 43%,respectively.The highest and lowestα-cellulose contents were found in two location of Mymensingh district.There was no correlation was found among the districts.Therefore,pulping of dhaincha from selected seven districts was carried out in kraft process at the conditions of 18%active alkali at 170℃ for 2 h.But the pulping properties did not show any mentionable distinction for place variation.Average pulp yield is 42.9%with kappa number 11.The highest brightness 85%was reached with D_(0)E_(p)D_(1)bleaching.The papermaking properties were very close to the conventional raw materials used in Bangladesh.Therefore,dhaincha can be used as a raw material for pulp production in Bangladesh.

Potassium hydroxide based biorefinery concepts for non-wood bioresources

The paper and paperboard production in 2016 in the world was 110.07 million tones.1 Bangladesh consumes only about 3.5~4 kg paper and board products per capita,while the developed countries consume about 300 kg/capita.Bangladesh’s consumption is also much lower than the world’s average(@50 kg/capita)and the Asia’s average(@50 kg/capita).2 To reach the world’s or Asia’s level,Bangladesh’s consumption of paper and board products needs to increase 10 folds.As forest resources are very limited in Bangladesh,alternative fibrous raw materials are required to achieve this goal.Therefore many studies have been carried out on alternative raw materials available in Bangladesh.

Phytochemical screening, antioxidant and cytotoxic activity of fruit extracts of Calamus tenuis Roxb

Objective:To investigate the antioxidant and cytotoxic activity of the fruits of Calamus tenuis Roxb.Methods:The preliminary phytochemical group tests were done,which revealed the presence of alkaloid,tannin,flavonoid and steroid.The dried fruit was extracted in soxhlet apparatus using petroleum ether,ethyl acetate and methanol.Antioxidant potential of each extract was evaluated using total phenol content,total flavonoid content,cupric reducing antioxidant capacity,1,1-diphenyl-2-picrylhydrazyl radical scavenging activity,and total antioxidant capacity determinations.Results:The extracts were found to possess moderate to high amounts of phenolic and flavonoid contents.In cupric reducing antioxidant capacity assay the extracts showed moderate reducing power which increases with concentration.Scavenging of 1,1-diphenyl-2-picrylhydrazyl radical was found to rise with concentration with lowest IC_(50)value for methanol extract,which was confirmed by total antioxidant activity test that shows highest(95 mg/g of extract)in ascorbic acid equivalent for methanol extract.In Brine shrimp lethality bioassay the methanol and petroleum ether extracts were found to be toxic to Brine shrimp nauplii,with LC_(50)of 25.53μg/mL and 28.07μg/mL respectively while the LC_(50)of the reference vincristine sulphate was 1.32μg/mL.Ethyl acetate extract was found to be moderately cytotoxic showing LC_(50)of 47.79μg/mL.Conclusions:The results of the present study suggest that the fruits of Calamus tenuis Roxb possess antioxidant and cytotoxic potential.Moreover,phytochemical screening reveals the presence of alkaloid,tannin,flavonoid and steroid,which may be responsible for the observed bioactivities.