REMOVAL OF CHROMIUM FROM AQUEOUS SOLUTION USING LOCALLY AVAILABLE INEXPENSIVE TARO AND WATER HYACINTH AS BIOSORBENT

In this investigation, locally available and inexpensive Taro and Water Hyacinth were used as biosorbents to remove chromium from synthetic wastewater. The removal of this metal ion from water in the batch and column method have been studied and discussed. Adsorption kinetics and equilibrium isotherm studies were also carried out. The material exhibits good adsorption capacity and the data follow both Freundlich and Langmuir models. Scanning Electronic Microscopic image was also used to understand the surface characteristics of biosorbent before and after biosorption studies. Effects of various factors such as pH, adsorbent dose, adsorbate initial concentration, particle size etc. were analyzed. The initial concentrations of chromium were considered 5-30mgL-1 in batch method and only 4mgL-1 in column method. The maximum chromium adsorbed was 1.64 mgg-1 and 4.44 mgg-1 in Batch method and 1.15 mgg-1 and 0.75 mgg-1 in Column method. Batch and Column desorption and regeneration studies were conducted. Column desorption studies indicated that both of these biosorbents could be reused for removing heavy metals. Results of the laboratory experiments show that the performance of Taro and Water Hyacinth prove that they can effectively be used as low cost biosorbents for the removal of chromium from wastewater. KEYWORDS:   adsorption; chromium removal; Taro; water hyacinth; batch method; column studie

Ligand based sustainable composite material for sensitive nickel(II) capturing in aqueous media

© 2019 Elsevier Ltd. Organic ligand based sustainable composite material was prepared for the detection and removal of nickel (Ni(II)) ion from contaminated water. The ligand was anchored based on the building-block approach. The carrier silica and ligand embedded composite material were characterized systematically. The detection and removal of Ni(II) ion operation was evaluated according to the solution pH, reaction time, detection limit, initial Ni(II) concentration and diverse co-existing metal ions. The detection limit of Ni(II) ion by the proposed composite material was 0.41 μg L-1. The detection and removal of Ni(II) ion was significantly influenced by the solution pH. However, the neutral pH 7.0 was chosen for sensitive and selective detection and removal of Ni(II) ion. The co-existing diverse metal ions were not interfered during the detection and removal of Ni(II) ion because of the high affinity of Ni(II) ion to composite material at the optimum experimental conditions. The Langmuir adsorption isotherm model was selected based on the materials morphology and applied to validate the adsorption isotherms according to the homogeneous ordered frameworks. The adsorption capacity was 199.19 mg g-1 as expected due to the high surface area of material. The adsorbed Ni(II) ion was completely eluted from the composite material with the eluent of 0.50 M HCl and the regenerated material was used in several cycles without deterioration in its initial performances. Therefore, it is expected to that the Facile composite material may hold huge potentials in applications and may be scaled up for commercial applications, including environmental detection and removal of Ni(II) ion

Novel micro-structured carbon-based adsorbents for notorious arsenic removal from wastewater

The contamination of groundwater by arsenic (As) in Bangladesh is the biggest impairing of a population, with a large number of peoples affected. Specifically, groundwater of Gangetic Delta is alarmingly contaminated with arsenic. Similar, perilous circumstances exist in many other countries and consequently, there is a dire need to develop cost-effective decentralized filtration unit utilizing low-cost adsorbents for eliminating arsenic from water. Morphological synthesis of carbon with unique spherical, nanorod, and massive nanostructures were achieved by solvothermal method. Owing to their intrinsic adsorption properties and different nanostructures, these nanostructures were employed as adsorption of arsenic in aqueous solution, with the purpose to better understanding the morphological effect in adsorption. It clearly demonstrated that carbon with nanorods morphology exhibited an excellent adsorption activity of arsenite (about 82%) at pH 3, remarkably superior to the two with solid sphere and massive microstructures, because of its larger specific surface area, enhanced acid strength and improved adsorption capacity. Furthermore, we discovered that iron hydroxide radicals and energy induced contact point formation in nanorods are the responsible for the high adsorption of As in aqueous solution. Thus, our work provides insides into the microstructure-dependent capability of different carbon for As adsorption applications

Levels of copper, zinc, iron and manganese in different fodders and feeds

Copper, zinc, iron and manganese concentration of different fodders and feeds were determined to understand whether it is below or above the critical level. In this study samples of rice straw, grasses, tree leaves and concentrate feeds were analysed for different trace elements contents. Rice straw contained high levels of Fe and Mn (>50 and >40 ppm), while the values of Cu and Zn were lower than the critical values (<8.0 and <30 ppm). Both the road side and fallow land grasses contained an adequate level of Cu, Zn, Fe and Mn. Almost all types of grasses contained higher levels of micro mineral (Cu, Zn, Fe and Mn) except Zn (27 ppm) in Khesari grass. Higher concentration of Cu, Fe and Mn were found in tree leaves compared to critical values. All tree leaves contained relatively lower amount of Zn except saora, jackfruit and banana leaves. Copper contents of almost all the concentrates were higher than the critical level. Zinc concentration was higher in rice bran, mustard oil cake, wheat bran, khesari bran, til oil cake, maize crushed (48.7, 35.1, 65.2, 33.2, 52.6 and 32.1 ppm, respectively) as against the critical value. However, Zinc content was lower in matikalai bran (19.9 ppm), wheat crushed (22.4 ppm) and broken rice (19.7 ppm). Most of the concentrates had higher amount of Fe and Mn compared to the critical level

Adsorptive removal of cesium from aqueous solution using oxidized bamboo charcoal

In this study, the air oxidized bamboo charcoal (BC) was investigated for cesium (Cs) adsorption from aqueous solution. The physicochemical properties of the adsorbent were evaluated systematically using the different techniques including BET, FESEM, FTIR, XPS and also the pHpzc value. Batch adsorption experiments were conducted to determine the effect of contact time, solution pH, initial Cs concentrations, temperature and also the presence of competitive ions on adsorption. The adsorption kinetic parameters confirmed the better fitting of pseudo-second order kinetic model. The isotherm data could be well described by the Langmuir isotherm model and the maximum monolayer adsorption capacity was 55.25 mg g−1. The high specific surface area and the porous structure with some acidic functional groups on the surface were obviously responsible for high Cs adsorption onto oxidized-BC. Thermodynamic parameters such as standard enthalpy, entropy, and Gibbs free energy were evaluated and it had been found that the adsorption process was favorable, spontaneous and endothermic in nature. In the competitive ions study, the presence of Na and K with their concentrations up to 12 mM did not strongly affect the removal of Cs by oxidized-BC. Therefore, the experimental results suggested that the oxidized-BC could be used as an effective adsorbent for significant Cs removal from aqueous solution considering the high adsorption capacity, short adsorption time and selective removal of Cs ions. Keywords: Bamboo charcoal, Air oxidation, Cesium, Adsorption, Kinetic, Isother

Use of Duckweed (Lemna perpusilla) as a Protein Source Feed Item in the Diet of Semi-Scavenging Jinding Layer Ducks

An experiment was conducted for a period of 75 days at farmers house to investigate the effect of feeding duckweed (Lemna perpusilla) that replaced conventional protein supplement mustard oil cake (MOC) in the diets for Jinding ducks. The experiment included a total of 84 laying ducks with four treatments and three replicates and seven ducks per replicate. The diets were based on rice by products where soybean meal and mustard oil cake as protein source. The control diet A contained 15% MOC and 5, 10 and 15% MOC was replaced with dry duckweed in diets B, C and D respectively. The birds were raised under extensive system and feeds were supplied two times daily before and after herded. The replacement of MOC by duckweed non-significantly depressed live weight gain (P&gt;0.05), egg weight (P&gt;0.05) and feed conversion efficiency (P&gt;0.05) but significantly increased egg production (P&lt;0.01) and profitability (P&lt;0.01) through reducing production cost of feeding. Body weight gain and egg productivity showed a linear declining trend as the proportion of duckweed in the diet was increased. Considering economic benefit it may be recommended to replace MOC by duckweed up to 15% level in the diet of laying duck

Cotton spinning waste as useful compost for organic Indian Spinach (Basella alba ) production in Bangladesh

Purpose This study aims to ascertain the physiochemical characteristics of the compost made from recycled cotton spinning waste (CSW) for Indian Spinach cultivation in Bangladesh.Method The physiochemical characteristics of the compost made of fresh cotton spinning waste (CSW), cotton spinning waste ash (CSWA), rice husk (RH), rice husk ash (RHA) with varying ratios following open air composting method was determined. The utility of the resulting compost was justified by applying it to Indian Spinach cultivation compared with chemical fertilizer and control (no-compost) treatments.Results Among the several composting options, the compost prepared by mixing 87% CSW + 13% CSW ash (C3) and 87% CSW + 13% rice husk (C4) was found to be the quality compost with a higher C/N ratio, P, K, S and a lower Pb content. The vegetative growth, yield and nutritional qualities were significantly affected by the compost characteristics compared to chemical fertilizer because of increased nutrient uptake and biostimulation functions. Moreover, Indian Spinach cultivated with CSW compost provided 64 BDTk. profits compared to 28 BDTk. in case of control that indicates 128% increase in profit for the compost than that of control.Conclusion The compost derived from the mixture of CSW+CSWA+RH+RHA substrates possesses an optimum moisture content (31.2%), pH (7.5), C/N ratio (16.8:1), macronutrients, and micronutrients that enable it to act as an alternative to chemical fertilizer. When it comes to yield and nutrition quality of the grown Indian Spinach, CSW based compost fared much better than chemical fertilizer in field test