Development of novel biosorbents in removing heavy metals from aqueous solution

University of Technology, Sydney. Faculty of Engineering and Information Technology.The contamination of water by toxic heavy metals including lead, cadmium, copper and zinc is a global problem. The release of these metals into the environment has become a serious health problem due to its toxicity. Progressively stricter discharge regulations on heavy metals have accelerated the search for highly efficient but economically feasible or alternative treatment methods for its removal. The use of low-cost and bio-waste or agro-waste as biosorbents for dissolved metal ions removals has shown potential to provide economic solutions to this environmental setback. Garden grass (GG), cabbage waste (CW), banana peels (BP), maple leaves (ML) and palm oil fruit shells (POFS) have been identified as potentially low cost and efficient biosorbent for the removal of toxic heavy metals from aqueous solution. Very simple methods were used to prepare these biosorbents. The collected GG, CW, BP, ML and POFS were washed, cut into pieces, dried in oven at 105°C, grounded into powder and used for experiments. The biosorbents were characterized by SEM, XRD, FTIR and BET tests. Surprisingly, all biosorbents showed that the surfaces of biosorbents’ particles are porous, heterogeneous structures, with uneven, asymmetric steps and pores which contained high internal spaces and posed higher specific surface area. The BET surface areas are 21.28, 1.027, 22.59, 10.94 and 39.76 m²/g for GG, CW, BP, ML and POFS, respectively. These biosorbents possesses many hydroxyl, carbonyl and phenyl functional groups (by FTIR test) and therefore, all these biosorbents are good contenders for water treatment and purification utilizations. Biosorption of all four metals [Pb(II), Cd(II), Cu(II) and Zn(II)] by GG, CW, BP, ML and POFS was found to be dependent on experimental conditions. The optimum biosorption were noted at pH 6-6.5, shaking speed of 120 rpm, initial concentration of 10 mg/1, dose of 5g/1, contact time of 2 h and particle sizes < 75μm. The increase of temperature negatively affected the metals biosorption and at room temperature the metals biosorption process is spontaneous and exothermic in nature. The acid medium (0.1N H₂SO₄) was found be a better eluent for regeneration of exhausted biosorbents and it could be reused 5-7 times with minor deviation of efficiency except CW. The efficient metal removing ability of biosorbents in both batch experiments and continuous flow fixed bed column bioreactors used to produce a biosorbent based metals removal system. It suggests that these novel biosorbents could lead to the development of a viable and cost-effective technology for metals removal from water and wastewaters. The prepared biosorbents were evaluated for the adsorption of Pb(II), Cd(II), Cu(II) and Zn(II) ions from single and multimetals aqueous solution by the batch method. The biosorption data were evaluated by equilibrium isotherms models. GG isotherm data posed better fitness with Langmuir, Freundlich and SIPS models as the R² lies between 0.991 and 0.999. Three-parameter models (Redlich-Peterson, Koble-Corrigan and SIPS) and two-parameter models (Langmuir and Freundlich) showed good fitness (R²: 0.991-1.0) with equilibrium adsorption data from CW. The biosorption data from BP are evaluated by Langmuir, SIPS, Redlich-Peterson, Radke-Prausnitz, and Brouers-Sotolongo and results showed a good fitness as the R² were between 0.998 to 1. Among the models three-parameter models such as Sips, Redlich-Peterson and Unilan showed good fitness with isotherm data from ML as the R² are 0.988-1.00. Likewise the equilibrium data from POFS posed proper agreement with three parameter models for biosorption of Cu(II). Significantly low RMSE and χ² values are found from all the used models which also signify the models fitness. The maximum Pb(II) adsorption capacities (qm) are 54.205, 61.267, 120.096 and 50.267 mg/g for GG, CW, BP and ML respectively; whereas it were 41.66, 22.123, 50.459 and 39.599 mg/g for Cd(II) biosorption. Among the biosorbents GG, ML and POFS showed good biosorption capacities for Cu(II) ion and the values are 58.34, 34.534 and 59.502 mg/g. The Zn(II) adsorption capacities are moderate and the magnitude of capacities are 57.53, 12.236, 51.896 and 29.94 mg/g for GG, CW, BP and ML respectively. A strong antagonisms were found among the metals ions [Pb(II), Cd(II), Cu(II) and Zn(II) ions] in the multimetals adsorption systems though Pb(II) and Cd(II) ions dominated. Surprisingly, the maximum reduction in capacities were also found for Pb(II) and Cd(II). The equilibrium and kinetics data for desorption were also evaluated the by isotherm models and kinetics models. Some data from GG and ML showed good agreement with models but most of the data did not pose appropriate fitness. The kinetics of metal removal by all biosorbents was extremely fast, reaching equilibrium in about 15-60 minutes which is showed the practical potentiality. The both pseudo-first-order and pseudo-second-order models was found to be the best fit (R²: 0.991-1.00) to describe the biosorption mechanism of Pb(II), Cd(II), Cu(II) and Zn(II) ions onto the biosorbents. This is implies that the adsorption mechanisms are both physisorption and chemisorption. As reaction constant, k₂ and nAV (from order and Avrami equation) values were greater than 1 suggested that biosorption reaction is more than one order. Intraparticle diffusion also involved for biosorption process. Along with this, Elovich and Fraction power models also posed good fitness with kinetics data. The metal removing capacity of CW was also tested in continuous flow fixed-bed column bioreactors for artificial wastewater. The removal capacities were 15.72, 62.23, 68.23 and 70.71 times higher than that obtained in a batch system for Pb(II), Cd(II), Cu(II) and Zn(II) ions. The appropriate service times to breakthrough and metals ions concentration were 5-10 h and 10 mg/1, respectively. The design of a continuous fixed bed column treatment system with CW biosorbent for Pb(II), Cd(II), Cu(II) and Zn(II) laden wastewater can be reached using the BDST, Yoon-Nelson and Clark breakthrough models. Elucidate the biosorption mechanisms is one of the aims for biosorption of metals. Fitness of pseudo-first-order and pseudo-second-order models suggested the biosorption are both physisorption and chemisorption. FTIR tests showed the functional groups which responsible ions exchange. Isotherm data fitted more with three-parameter models which signifies the adsorption onto heterogeneous surface. It is also found from SEM and XRD data. Thus, it could not be ascertained from the results which single mechanism involved for metals biosorption. However, it could presume that combination of all mechanisms with complexation are responsible for Pb(II), Cd(II), Cu(II) and Zn(II) ions and therefore, high biosorption capacities were found

Feasibility study of cassava meal in broiler diets by partial replacing energy source (corn) in regard to gross response and carcass traits

Day-old unsexed broiler chicks (Cobb 500) were used to investigate the growth responses and meat yield traits by nourishing them under four dietary treatment group in inclusion of cassava meal with partial substitution of valuable energy source (maize or corn). A total of 260 birds were assigned randomly into four dietary treatments [T1 (0%); T2 (10%); T3 (20%), and T4 (30%)]; each replicated 5 times, 13 birds/replicate in a completely randomized design. Birds were reared with ad libitum feeding, similar housing, and environmental management condition from d1-35 days. Growth responses of broilers in terms of feed intake, body weight, feed conversion ratio (FCR), livability and meat yield traits were assessed in this study. Except for first week, the feed intake of birds on cassava treated diets up to 21 and 35 days was significantly (p&lt;0.001) higher than the non-cassava or control diet (T1). Feed intake of broilers on cassava treated diet (T4 ) had the highest (2795.8 g/b) while the birds of control (T1) diet group consumed the lowest feed (2771.9 g/b) at 35 day. Live weight decreased (p&lt;0.001) with the inclusion of cassava meal diets up to 21 day only; and live weights up to 7 and 35 days were identical between treatment. FCR up to 21 day was improved (p&lt;0.001) on control diet (T1) and deteriorated on cassava treated diets. FCR values up to 7 and 35 days were unaffected by all the treatment groups. Neither the livability nor the meat yield traits (thigh, breast, drumstick, shank, neck, giblet, wing and dressing yield) of broiler chickens was influenced by the dietary treatments regardless of feeding broiler chickens with cassava or non-cassava diets in this study. It may be deduced based on the present findings that, cassava tuber meal might be a potential ingredient to replace the costly maize up to 300 g kg-1 without affecting growth performance of the broiler chickens. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17846 Int. J. Agril. Res. Innov. &amp; Tech. 3 (2): 59-65, December, 201

Evolution of microgrids with converter-interfaced generations: Challenges and opportunities

© 2019 Elsevier Ltd Although microgrids facilitate the increased penetration of distributed generations (DGs) and improve the security of power supplies, they have some issues that need to be better understood and addressed before realising the full potential of microgrids. This paper presents a comprehensive list of challenges and opportunities supported by a literature review on the evolution of converter-based microgrids. The discussion in this paper presented with a view to establishing microgrids as distinct from the existing distribution systems. This is accomplished by, firstly, describing the challenges and benefits of using DG units in a distribution network and then those of microgrid ones. Also, the definitions, classifications and characteristics of microgrids are summarised to provide a sound basis for novice researchers to undertake ongoing research on microgrids

Bioefficacy of Plant Extracts to Control Cercospora Leaf Spot of Mungbean (Vigna radiata)

The experiment was conducted at Bangladesh Agricultural Research Institute farm, Joydebpur, Gazipur during March to July 2007 to evaluate the bioefficacy of some plant extracts in controlling Cercospora leaf spot of mungbean. Six indigenous plant species i.e. Neem leaves extract (1:4 w/v), Garlic cloves extract (1:5 w/v), Biskatali leaves extract (1:4 w/v), Alamanda leaves extract (1:6 w/v), Arjun leaves extract (1:4 w/v) and Debdaru leaves extract (1:5 w/v) were used in this experiment. The experiment was laid out in RCBD with seven treatments and four replications. Data on disease incidence, severity, yield contributing characters and yield of mungbean were recorded. Naturally, infection of the disease was considered in this experiment. The lowest disease incidence (7.33%) at 60 DAS was found in T1. Lowest and similar disease severity (PDI= 4.55) was found in T2 and T3 at the same DAS. Neem extract treated plots gave better response in yield (1.26 t ha-1) and all the yield contributing parameters like inflorescences plant-1 (13.45), tallest plant (51.44 cm), the maximum number of pods plant-1 (26.81), length of pod (8.56 cm), number of seeds pod-1 (12.64) and 1000 seeds weight (27.33 g) followed by T2 and T3. The highest disease incidence (26.50%) and disease index (13.65%) were recorded in treatment T7 at 60 DAS. Yield and all yield contributing factors were lowest in same treatment. The results of the experiment suggested that the use of neem leaves extracts are effective for minimizing Cercospora leaf spot incidence, severity and increasing yield of mungbean. Int. J. Agril. Res. Innov. &amp; Tech. 3 (1): 60-65, June, 2013 DOI: http://dx.doi.org/10.3329/ijarit.v3i1.1609

Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells

Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc = 0.518 V, jsc = 28.79 mA cm(-2), fill factor = 64.02%, and a promising power conversion efficiency of η = 9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost

Strong enhancement of Jc in binary and alloyed in-situ MgB2 wires by a new approach: Cold high pressure densification

Cold high pressure densification (CHPD) is presented as a new way to substantially enhance the critical current density of in situ MgB2 wires at 4.2 and 20 K at fields between 5 and 14 T. The results on two binary MgB2 wires and an alloyed wire with 10 wt.% B4C are presented The strongest enhancement was measured at 20K, where cold densification at 1.85 GPa on a binary Fe/MgB2 wire raised both Jcpara and Jcperp by more than 300% at 5T, while Birr was enhanced by 0.7 T. At 4.2K, the enhancement of Jc was smaller, but still reached 53% at 10 T. After applying pressures up to 6.5 GPa, the mass density dm of the unreacted (B+Mg) mixture inside the filaments reached 96% of the theoretical density. After reaction under atmospheric pressure, this corresponds to a highest mass density df in the MgB2 filaments of 73%. After reaction, the electrical resistance of wires submitted to cold densification was found to decrease, reflecting an improved connectivity. A quantitative correlation between filament mass density and the physical properties was established. Monofilamentary rectangular wires with aspect ratios a/b < 1.25 based on low energy ball milled powders exhibited very low anisotropy ratios, Gamma = Jcpara/Jcperp being < 1.4 at 4.2 K and 10T. The present results can be generalized to alloyed MgB2 wires, as demonstrated on a wire with B4C additives. Based on the present data, it follows that cold densification has the potential of further improving the highest Jcpara and Jcperp values reported so far for in situ MgB2 tapes and wires with SiC and C additives. Investigations are under work in our laboratory to determine whether the densification method CHPD can be applied to longer wire or tape lengths.Comment: Submitted to Superconductors Science and Technolog

Effect of Sodium Treatment on the Performance of Electrostatic Spray Assisted Vapour Deposited Copper-poor Cu(In,Ga)(S,Se)2 Solar Cells

In our work, eco-friendly, non-vacuum and low cost Electrostatic Spray Assisted Vapour Deposition (ESAVD) method has been used to produce Cu(In,Ga)(S,Se) 2 (CIGS) solar cells. Copper (Cu) deficient (Cu/In + Ga = 0.76) CIGS films were designed to avoid the rather dangerous KCN treatment step for the removal of conductive minor phases of Cu 2 S/Cu 2 Se. A simple sodium (Na) treatment method was used to modify the morphology and electronic properties of the absorber and it clearly improved the solar cell performance. The SEM and XRD results testified a slightly increase of the grain size and (112) crystal orientation in the Na-incorporated CIGS thin films. From the Mott-schottky results, it can be seen that the functions of the Na treatment in our non-vacuum deposited CIGS are mainly used for defect passivation and reduction of charge recombination. Photovoltaic characteristics and j-V curve demonstrated that the dipping of CIGS films in 0.2 M NaCl solution for 20 minutes followed by selenization at 550 °C under selenium vapor resulted in the optimum photovoltaic performance, with j sc , V oc , FF and η of the optimized solar cell of 29.30 mA cm -2 , 0.564 V, 65.59% and 10.83%, respectively

Performance and Economic Suitability of Three Fast Growing Broiler Strains Raised Under Farming Condition in Bangladesh

The performance and profitability of three commercial broiler strains reared under farming system were investigated in this study. Day-old broiler chicks (n=156) of three different commercial strains (Hubbard classic, Cobb-500 and MPK) were assigned to three treatment groups in a completely randomized block design, each treatment replicated four times, 13 birds per replicate. The birds were reared from d1 to 35 days of age with similar housing, feeding and environmental management condition. Regarding to all parameters collected, live weight and body weight gain were higher (P&lt;0.001) in T2(Cobb-500) group, while the birds of T3 (MPK) group were the lowest. Birds of T1(Hubbard Classic) and T2 (Cobb-500) strain group consumed higher (P&lt;0.001) feeds, while the birds of T3(MPK) had the lowest feed intake. Cobb-500 broiler strain achieved superior (P&lt;0.001) FCR, while the birds of T1 (Hubbard classic) strain group had poorer FCR. Liveability of the broiler strains was unaffected by all the treatment groups. Higher net profit and lower production cost observed in T2(Cobb-500) group than those of other strains, although the difference between the treatment groups was similar. The highly significant measurements of live body weight, weight gain and better FCR values were recorded for Cobb-500 broiler strain, followed by Hubbard classic and MPK, respectively. In conclusion, Cobb-500 broiler strain is appeared to be the most economic to rear amongst the three broiler strains investigated here in response to their performance records. DOI: http://dx.doi.org/10.3329/ijarit.v1i1-2.13931 Int. J. Agril. Res. Innov. &amp; Tech. 1 (1&amp;2): 37-43, December, 201

Evaluation of growth of Chlorella ellipsoidea in different culture media

An experiment was conducted to evaluate the growth of Chlorella ellipsoidea in three different media viz,. medium I (pulse bran), medium II (soil extract) and medium III (inorganic) under the natural environmental conditions. The alga, C. ellipsoidea, reached maximum cell density of 56.32 × 106 cells ml-1 in 10 days in medium I (pulse bran), maximum cell density of 102.99 × 106 cells ml-1 in 11 days in medium II (soil extract) and maximum cell density of 64.23 × 106 cells ml-1 in 12 days in medium III (inorganic medium). The ranges of water temperature, air temperature and light intensity were 22 to 32ºC, 22 to 34ºC and 2.11 to 4.31 (× 103) lux, respectively during the culture period. The average sunshine period was 7.65 ± 1.57 hours. Total alkalinity, free CO2, pH, NO3-N, PO4- P of algal culture medium I, medium II and medium III were 220, 200 and 150 mg L-1 ; 26, 9 and 19 mg L-1; 7.9, 7.6 and 7.5; 45, 45 and 133.33 mg L-1; 10.9, 15.1 and 37.06 mg L-1, respectively. Cell densities of cultures of C. ellipsoidea under three treatments I, II and III, it can be concluded that cell densities under 3 treatments are significantly different (F=39.78) and treatment II (soil extract medium) is the best for algal (C. ellipsoidea) culture among three treatments. DOI: http://dx.doi.org/10.3329/ijarit.v4i2.22636 Int. J. Agril. Res. Innov. &amp; Tech. 4 (2): 6-10, December, 201

Isolation and selection of Bradyrhizobium from the root nodules of indigo plants (Indigofera tinctoria L.)

This research was conducted from 2004 to 2005 to isolate and select Bradyrhizobium from the root nodules of indigo plants (Indigofera tinctoria L.). For isolation of Bradyrhizobium, root nodules were collected from indigo plants. Fourteen Bradyrhizobium isolates were identified depending on colony, morphological and biochemical characteristics. Out of fourteen isolates, six (HSTU-IR2, HSTU-IR3, HSTU-IR4, HSTU-IR9, HSTU-IR10 and HSTU-IR14) were found promising with respect to nodulation, shoots and roots weights and N fixation by the indigo plants grown inside the Leonard Bottle Jar Assembly (LBJA).Key words: Bradyrhizobium, isolation, selection, root nodules, indigo plants