Kinetic studies for Ni(II) biosorption from industrial wastewater by Cassia fistula (Golden Shower) biomass

The present study explores the ability of Cassia fistula waste biomass to remove Ni(II) from industrial effluents. C. fistula biomass was found very effective for Ni(II) removal from wastewater of Ghee Industry (GI), Nickel Chrome Plating Industry (Ni-Cr PI), Battery Manufacturing Industry (BMI), Tanner Industry: Lower Heat Unit (TILHU), Tannery Industry: Higher Heat Unit (TIHHU), Textile Industry: Dying Unit (TIDU) and Textile Industry: Finishing Unit (TIFU). The initial Ni(II) concentration in industrial effluents was found to be 34.89+/-0.01, 183.56+/-0.08, 21.19+/-0.01, 43.29+/-0.03, 47.26+/-0.02, 31.38+/-0.01 and 31.09+/-0.01mg/L in GI, Ni-Cr PI, BMI, TILHU, TIHHU, TIDU and TIFU, respectively. After biosorption the final Ni(II) concentration in industrial effluents was found to be 0.05+/-0.01, 17.26+/-0.08, 0.03+/-0.01, 0.05+/-0.01, 0.1+/-0.01, 0.07+/-0.01 and 0.06+/-0.01mg/L in GI, Ni-Cr PI, BMI, TILHU, TIHHU, TIDU and TIFU, respectively. The % sorption Ni(II) ability of C. fistula from seven industries included in present study tend to be in following order: TILHU (99.88)>GI (99.85) approximately BMI (99.85)>TIFU (99.80)>TIHHU (99.78)>TIDU (99.77)>Ni-Cr PI (90.59). Sorption kinetic experiments were performed in order to investigate proper sorption time for Ni(II) removal from wastewater. Batch metal ion uptake capacity experiments indicated that sorption equilibrium reached much faster in case of industrial wastewater samples (480min) in comparison to synthetic wastewater (1440min) using same biosorbent. The kinetic data were analyzed in term of pseudo-first-order and pseudo-second-order expressions. Pseudo-second-order model described well the sorption kinetics of Ni(II) onto C. fistula biomass from industrial effluents in comparison to pseudo-first-order kinetic model. Due to unique high Ni(II) sorption capacity of C. fistula waste biomass it can be concluded that it is an excellent biosorbent for Ni(II) uptake from industrial effluents.     

Buck-boost converter feedback controller design via evolutionary search

Buck-boost converters are switched power converters. The model of the converter system varies from the ON state to the OFF state and hence traditional methods of controller design based on approximate transfer function models do not yield good dynamic response at different operating points of the converter system. This article attempts to design a feedback controller for a buck-boost type dc–dc converter using a genetic algorithm. The feedback controller design is perceived as an optimisation problem and a robust controller is estimated through an evolutionary search. Extensive simulation and experimental results provided in the article show the effectiveness of the new approach.     

Analog baseband chain of synthetic aperture radar (SAR) receiver

An analog baseband chain for a synthetic aperture radar receiver implemented in a 130 nm CMOS technology is presented in this paper. Occupying 0.23 mm² of silicon area, the baseband chain consists of a three-stage variable gain amplifier (VGA), a 5th-order gm-C low-pass filter (LPF) and an output buffer. The gain of the chain can be controlled by tuning the control voltages of the VGA and has a range from 25 to 34 dB. 8 dB of the gain is embedded into the LPF. The bandwidth of the LPF is programmable from 100 to 190 MHz by means of capacitor matrices. The chain, which uses a 1.2 V supply voltage, achieves an input-referred noise density of 4 nV/ $ \sqrt {\text{Hz}} $ and an in-band IIP3 of ?46 dBV rms.     

Effect of NaOH on pretreatment of Gossypium herbaceum

In present study, the substrate Gossypium herbaceum (cotton stalks) was treated with sodium hydroxide to investigate its greatest promising use as an economical substrate for bioethanol production. Initially, 2 mm mesh size cotton stalks were soaked in various concentrations of NaOH (1–3%) for different soaking intervals of 2, 4, 6, 12, 24, and 48 h. The results showed that the cellulose content and delignification increased with the increase in the concentration of alkali and soaking time. However, the maximum cellulose and delignification (60.6% and 51.5%) were observed with 2.5% NaOH after 24 h of soaking. In physiochemical pretreatment, the maximum cellulose content (73.19%) was achieved with 2.5% NaOH at 121°C after 60 min while delignification was found to be 77.7%. All these results of the present study indicate that a suitable concentration of alkali as well as an autoclaving period at specific temperature are very much crucial to expose the maximum cellulosic contents prior to employing cotton stalks as substrates for bio-fuel production.     

Okra (Hibiscus esculentus) seed oil for biodiesel production

Biodiesel was derived from okra (Hibiscus esculentus) seed oil by methanol-induced transesterification using an alkali catalyst. Transesterification of the tested okra seed oil under optimum conditions: 7:1 methanol to oil molar ratio, 1.00% (w/w) NaOCH₃ catalyst, temperature 65 °C and 600 rpm agitation intensity exhibited 96.8% of okra oil methyl esters (OOMEs) yield. The OOMEs/biodiesel produced was analyzed by GC/MS, which showed that it mainly consisted of four fatty acids: linoleic (30.31%), palmitic (30.23%), oleic (29.09%) and stearic (4.93%). A small amount of 2-octyl cyclopropaneoctanoic acid with contribution 1.92% was also established. Fuel properties of OOMEs such as density, kinematic viscosity, cetane number, oxidative stability, lubricity, flash point, cold flow properties, sulfur contents and acid value were comparable with those of ASTM D 6751 and EN 14214, where applicable. It was concluded that okra seed oil is an acceptable feedstock for biodiesel production.     

Exploiting the potential of polyphenolic biomordants in environmentally friendly coloration of wool with natural dye from Butea monosperma flower extract

Coloration of textiles with natural dyes involves huge consumption of chemicals; mainly, metal salt mordants, which pose serious environmental challenges. To mitigate this pollution, more and more environmentally friendly, biodegradable, biocompatible and renewable products should be popularized in dyeing industry. This paper proposes a sustainable and metal salt-free dyeing of wool samples by employing natural mordants extracted from pomegranate peel (Punica granatum L), gallnut (Quercus infectoria L) and catechu (Acacia catechu). The color parameters of dyed wool samples were greatly found to be dependent on the chemical compounds present in respective biomordants and their interaction ability with the functional groups of wool and the dye molecules. The investigated biomordants exhibit different interactions with coloring compounds of Butea monosperma (palas) dye resulting in deep brown, olive green, dark brown, cinnamon, burgundy, and yellowish hues on wool. All the biomordants selected in this study improved dye performance and resulted in a broad beautiful spectrum of colors with acceptable fastness properties. The results encourage the search and exploitation of new plant species as a source of biomordants to replace metallic and toxic mordants currently used in textile industry.     

Light Fastness and Shade Variability of Tannin Colorant Dyed Wool with the Effect of Mordanting Methods

Mordanting methods effect on color characteristics and fastness properties, particularly light fastness were evaluated in this study. Effect of metal mordants and their combinations on wool dyeing with Terminalia chebula natural dye were investigated and correlation between dye structures, effect of metal mordant and mordanting methods were established. Results reveal that T. chebula can be used as yellow dye with or without metal mordants to get a variable range of shades on wool with good color strength and fastness properties, and appreciable shade variations with mordanting methods observed. Color performances of dyed substrate indicated substantial improvement in depth of shades and color fastness in case of mordanted samples. Pre-mordanting with tin and post-mordanting with alum proved to be most effective for increasing K/S values of the dyed substrate under the optimum dyeing conditions.     

Management of hyperuricemia through dietary polyphenols as a natural medicament: A comprehensive review

Hyperuricemia, a condition due to high serum uric acid level and is notorious to health. It is considered to be a potent risk factor for gout and dramatically associated in the development of many chronic diseases such as malignant tumor, cardiovascular disorders and renal failure. Modern innovative medicinal and therapeutic interventions are underlying these days to combat hyperuricemia. Previously reported studies revealed the significant impact of dietary polyphenols (e.g. anthocyanins, phenolic acids, flavonoids etc.) against hyperurecemia disorder. Dietary plant polyphenols, unlike anti- hyperuricemic agents, are not reported to have any side effects in curing hyperuricemia. The current comprehensive review figure outs the use of dietary polyphenols as a natural remedy for the management of hyperuricemia. The sources, affiliated pathways, mode of actions and factors affecting their efficiency to prevent hyperuricemia are deeply discussed in this article. Additionally, limitations and suggestions regarding previously reported studies are also highlighted.     

Effect of Binary and Ternary Combination of Metal Salt Mordants on Dyeing and Fastness Properties of Natural Protein Fibre with Juglans regia L. Dye

The present article focuses on the effect of different combinations of metal mordants on color characteristics and fastness properties of natural dye extracted from Juglan regia L bark powder. The influence of different types of mordant combinations such as alum + ferrous sulphate, alum + stannous chloride, ferrous sulphate + stannous chloride, and alum + ferrous sulphate + stannous chloride on color parameters has been investigated in terms of CIELab (L*, a*, b*, c*, and h°) and K/S values. The fastness properties with respect to light, washing, and crocking of developed shades were determined according to ISO and AATCC test methods. Based on the experimental results, it has been found that 96 shades with novel and fashionable hues were produced by the use of these metal salt combinations. It was also found that all mordanted samples had satisfactory light and wash fastness ratings. Dry rub fastness was found relatively better than wet rub fastness.