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181.

Introduction

A biosorbent was developed by simple dried Agaricus bisporus (SDAB) and effectively used for the biosorption of cationic dyes, Crystal Violet and Brilliant Green.

Materials and methods

For the evaluation of the biosorbent system, all the batch equilibrium parameters like pH, biomass dose, contact time, and temperature were optimized to determine the decolorization efficiency of the biosorbent. The maximum yields of dye removal were achieved at pH 4.0 for Crystal Violet (CV) and pH 5.0 for Brilliant Green (BG), which are closer to their natural pH also.

Result and discussion

Equilibrium was established at 60 and 40 min for CV and BG, respectively. Pseudo first-order, pseudo second-order, and intraparticle-diffusion kinetic models were studied at different temperatures. Isotherm models such as Freundlich, Langmuir, and Dubinin–Radushkevich were also studied. Biosorption processes were successfully described by Langmuir isotherm model and the pseudo second-order kinetic model.

Conclusions

The biosorption capacity of A. bisporus over CV and BG were found as 21.74 and 12.16 mg gm?1. Thermodynamic parameters indicated that the CV and BG dye adsorption onto A. bisporus is spontaneous and exothermic in the single and ternary systems. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used for the surface morphology, crystalline structure of biosorbent, and dye–biosorbent interaction, respectively. This analysis of the biosorption data confirmed that these biosorption processes are ecofriendly and economical. Thus, this biomass system may be useful for the removal of contaminating cationic dyes.  相似文献   
182.
Kumar A  Sharma B  Pandey RS 《Chemosphere》2011,83(4):492-501
In the present study, two fresh water fishes namely, Channa punctatus and Clarias batrachus, were exposed to three sub-acute concentrations of synthetic pyrethroid, cypermethrin, for 96 h to evaluate the role of amino acids in fulfilling the immediate energy needs of fishes under pyrethroid induced stress as well as to find out the mechanism of ammonia detoxification. The experiments were designed to estimate the levels of free amino acid, urea, ammonia and the activities of aspartate aminotransferase (AAT), alanine aminotransferase (AlAT), glutamate dehydrogenase (GDH), glutamine synthetase (GS) and arginase in some of the vital organs like brain, gills, liver, kidney and muscle of both fish species. The significant decrease in the levels of amino acids concomitant with remarkable increase in the activities of AAT, AlAT and GDH in these vital tissues of fish species elucidated the amino acid catabolism as one of the main mechanism of meeting out the immediate energy demand of the fishes in condition of cypermethrin exposure. The levels of ammonia were significantly increased at 10% of 96 h LC(50) of cypermethrin in the different organs such as brain, gills, liver, kidney and muscle of both fish species while 15% and 20% concentrations of 96 h LC(50) of cypermehrin registered remarkable decline in both fish species. The differential increment in the activities of GDH, GS and arginase and in the level of urea established three different alternative mechanisms of ammonia detoxification. The results indicated that in C. punctatus, the prevalent mode of nitrogen excretion is in the form of conversion of ammonia into glutamine and glutamate while in C. batrachus, the excessive nitrogen is excreted in the form of urea synthesized from ammonia.  相似文献   
183.
The steady increase in production of corn based ethanol fuel has dramatically increased the supply of its major co-product known as distiller’s dried grain with solubles (DDGS). Large amount of DDGS and corn flour are used as an animal feed. The elusieve process can separate DDGS or corn flour into two fractions: DDGS fraction with enhanced protein and oil content or corn flour fraction with high starch content, and hull fiber. This study investigated the feasibility of using fiber from DDGS and corn grain as alternative fillers to wood fiber in high density polyethylene (HDPE) composites made with two different sources of polymers. Two fiber loading rates of 30 and 50% were evaluated for fiber from DDGS, corn, and oak wood (control) to assess changes in various physical and mechanical properties of the composite materials. Two HDPE polymers, a bio-based HDPE made from sugarcane (Braskem), and a petroleum based HDPE (Marlex) were also compared as substrates. The biobased polymer composites with DDGS and corn fibers showed significantly lower water absorption than the Marlex composite samples. The Braskem composite with 30% DDGS fiber loading showed the highest impact resistance (80 J/m) among all the samples. The flexural properties showed no significant difference between the two HDPE composites.  相似文献   
184.
Agriculture is one of the prime activities of the hill people residing in the northwestern Indian Himalaya. However, poor soil fertility in these areas is a big hurdle to sustainable farming. The effects of washout of topsoil and its nutrients, year after year, due to the abundance of snowfall, avalanches, landslides and erosion further add to the woes of the farmers. In the cold and harsh climatic conditions of the region, with grass and vegetation cover being scanty, it is not possible to maintain large herds of cattle for the adequate production of farmyard manure. Faced with this situation, the locals have relied heavily on obtaining organic manure derived from composting of human excreta. In earlier times the dire necessity of the farmers helped them overcome the revulsion associated with the practice of handling human excreta, but now with the advent of modernisation and the easy availability of chemical fertilisers, the people are distancing themselves from this age-old practice. More and more people are opting for modern toilets and leaving behind the traditional toilets that made possible the harvesting of manure from night-soil. As a result, this primitive practice is on the verge of extinction. This eco-friendly practice, that has sustained the land for so many generations, needs to be continued and strengthened as the long-term consequences of excessive and indiscriminant use of chemical fertilisers are becoming too obvious to ignore. Traditional knowledge needs to be combined with modern scientific know-how to make this practice safer and more acceptable. If the composting operation is managed properly, the handling will be less loathsome and the concerns of health and hygiene too will stand addressed. The present study attempts a detailed profile of the practice of 'supplementing soil nutrients through biocomposting of night-soil' in the cold desert region of Lahaul Valley. Four villages running from the northwestern part to the southeastern part of the valley were selected. The study is broadly based on a direct interview of heads of the various households in the selected villages of Kuthar (2600m), Hinsa (2700m), Jahlma (3000m) and Khoksar (3200m).  相似文献   
185.
Environmental Science and Pollution Research - Over the years, supplementary cementitious materials (SCM) have been successfully utilized in concrete buildings, but they have been rarely exploited...  相似文献   
186.
Environmental Science and Pollution Research - The Swachh Bharat Mission undertaken by the Government of India (GoI) has been successful in accomplishing this objective within a short period...  相似文献   
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