scholarly journals Removal of Chromium(III) and Other Physical Parameters from Chrome Tan Wastewater and Recovery of Chromium from the Precipitating Sludge

2020 ◽  
Vol 3 (2) ◽  
pp. 64-77
Author(s):  
Md. Minhaz Uddin ◽  
Jawad Hasan ◽  
Md. Didarul Islam ◽  
Ashiqur Rahaman ◽  
Sayed Md. Shamsuddin
Keyword(s):  
Environmental Pollution ◽  
Physicochemical Parameters ◽  
Chromium Concentration ◽  
Physical Parameters ◽  
Optimum Ph ◽  
Removal And Recovery ◽  
Maximum Removal ◽  
Cr Removal

This study was adopted to investigate the removal of Cr(III)and other physicochemical parameters of chrome tan wastewater. For this purpose, three precipitating agents, CaCO3, NaHCO3, and MgO, were used to treat chrome tan wastewater. After treatment, it was found, in three different dose trials, that each agent removed almost 97-99.5 % of chromium. At the same time, it was observed that with the increase of doses, removal percentage of TDS, conductivity, and turbidity of effluent were reduced. In the case of NaHCO3 and CaCO3, Cr(III) removal percentage at optimum pH was found to be 99.97% and 99.95% respectively, whereas the maximum removal percentage for MgO was found to be 99.98%. The NaHCO3 and CaCO3 were found to be comparable to MgO for Cr(III) removal from chrome tan wastewater. The recovered chromium concentration in the sludge for NaHCO3 and CaCO3 were also similar to that of MgO. This research suggests that these two precipitating agents can be used in the same way as MgO, for Cr removal and recovery treatments. Moreover, this recovered chromium can be reused, thus reducing the environmental pollution.

Effect of temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37

2021 ◽  
Vol 66 (1) ◽  
pp. 72-79
Author(s):  
Thuoc Doan Van ◽  
Hung Nguyen Phuc
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Animal Feed ◽  
Culture Conditions ◽  
Effect Of Temperature ◽  
Physical Parameters ◽  
Original Activity ◽  
Optimum Ph ◽  
Production Activity ◽  
Ph Range

The effect of physical parameters such as temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37 was investigated. The results indicated that the optimum culture conditions for enzyme activity were pH 7.0 and 35 oC. The optimum pH and temperature for enzyme activity were 6.0 and 70 oC. The crude enzyme was found to be stable in the pH range of 5.0 to 7.0. The enzyme was stable for 1 h at a temperature from 30 to 80 oC; nearly 100% of enzyme activity remained at temperatures of 30 - 40 oC, and about 34% of original activity remained at a temperature of 80 oC. These features demonstrated that α-amylase from B. subtilis V37 can be applied in many areas such as the food, fermentation, and animal feed industries.

Performance of Moringa oliefera as a biosorbent for chromium removal

2010 ◽  
Vol 62 (5) ◽  
pp. 1106-1111 ◽  
Author(s):  
K. Ghebremichael ◽  
N. Gebremedhin ◽  
G. Amy
Keyword(s):  
Waste Product ◽  
Chromium Concentration ◽  
Seed Processing ◽  
Metals Removal ◽  
Wastewater Systems ◽  
Seed Husk ◽  
Whole Seed ◽  
By Products ◽  
Moringa Oleifera Seed ◽  
Maximum Removal

This study investigated adsorption of chromium on to a bio-adsorbent, Moringa oleifera seed. Different by-products of the seed processing were used as adsorbents. These include: the Whole Seed Powder (WSP), the Residue after Coagulant Extraction (RaCE) and an Activated Carbon (AC) prepared from the seed husk. Adsorption studies for the removal of Cr(III) and Cr(VI) were carried out in batch experiments and the effects of adsorbent dosage, contact time, pH and initial chromium concentration were analysed. Experimental results showed that maximum removal of Cr(III) and Cr(VI) was observed at pH 7 and pH 2, respectively. The percentage removals of Cr(III) by WSP, RaCE and AC were: 97, 94 and 99.9%, respectively. And the percentage removals of Cr(VI) by RaCE and AC were 47 and 83.2%, respectively. RaCE showed similar adsorption capacity to the WSP, which indicates that it is possible to extract a coagulant and use the waste product for adsorption. By using the RaCE, residual dissolved organic carbon in the treated water was significantly reduced compared to using the WSP. These results indicate that biomaterials can be considered as potential adsorbents for heavy metals removal from water or wastewater systems.

scholarly journals Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Ph Value ◽  
Batch Experiments ◽  
Modified Zeolite ◽  
Optimum Ph ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Correlation Factors ◽  
Maximum Removal

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.

scholarly journals Removal of Cd(II) Ions from Simulated Wastewater by HCl Modified Cucumis sativus Peel: Equilibrium and Kinetic Study

2014 ◽  
Vol 7 ◽  
pp. ASWR.S16488 ◽  
Author(s):  
Ruchi Pandey ◽  
Nasreen Ghazi Ansari ◽  
Ram Lakhan Prasad ◽  
Ramesh Chandra Murthy
Keyword(s):  
Cucumis Sativus ◽  
Adsorption Process ◽  
Order Reaction ◽  
Ion Concentration ◽  
Second Order Reaction ◽  
Monolayer Adsorption ◽  
Optimum Ph ◽  
Pseudo Second Order ◽  
Simulated Wastewater ◽  
Maximum Removal

This paper describes the adsorption of Cd(II) ions from aqueous solutions by modified Cucumis sativus peel (CSP) by HCl treatment. The optimum pH, adsorbent mass, contact time, and initial ion concentration were determined. The maximum removal efficiency was 84.85% for 20 mg/L Cd(II) ion at pH 5. The adsorption isotherms were obtained using concentrations of the metal ions ranging from 5 to 150 mg/L. The adsorption process follows Langmuir isotherm and pseudo-second-order reaction kinetics. CSPs exhibit monolayer adsorption capacity of 58.14 mg/g at 298 K. The paper also discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results establish that the adsorption process was spontaneous and endothermic under normal conditions.

scholarly journals Removal of potentially toxic elements from aqueous solutions and industrial wastewater using activated carbon

2017 ◽  
Vol 75 (11) ◽  
pp. 2571-2579 ◽  
Author(s):  
Muhammad Sajjad ◽  
Sardar Khan ◽  
Shams Ali Baig ◽  
Saduf Munir ◽  
Alia Naz ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Industrial Wastewater ◽  
Toxic Elements ◽  
Potentially Toxic Elements ◽  
Column Experiments ◽  
Langmuir Isotherm Model ◽  
Key Issues ◽  
Maximum Removal ◽  
Cr Removal

Water contamination with potentially toxic elements (PTEs) has become one of the key issues in recent years that threatens human health and ecological systems. The present study is aimed at removing PTEs like cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) from aqueous solutions and industrial wastewater using activated carbon (AC) as an adsorbent through different batch and column experiments. Results demonstrated that the removal of PTEs from aqueous solutions was highly pH dependent, except for Cr, and the maximum removal (>78%) was recorded at pH 6.0. However, maximum Cr removal (82.8%) was observed at pH 3.0. The adsorption reached equilibrium after 60 min with 2 g of adsorbent. Coefficient (R2) values suggested by the Langmuir isotherm model were 0.97, 0.96, 0.93 and 0.95 for Cd, Cr, Cu and Pb, respectively, indicating the fit to this model. In column experiments, the maximum removal of PTEs was observed at an adsorbent bed height of 20 cm with the optimal flow rate of 3.56 mL/min. Furthermore, PTEs removal by AC was observed in the order of Cu > Cd > Pb > Cr. Findings from this study suggest that AC could be used as a promising adsorbent for simultaneously removing several PTEs from wastewaters.

Low cost Fenton's oxidative degradation of 4-nitroaniline using iron from laterite

2016 ◽  
Vol 74 (8) ◽  
pp. 1919-1925 ◽  
Author(s):  
A. S. Amritha ◽  
B. Manu
Keyword(s):  
Low Cost ◽  
Oxidative Degradation ◽  
Cost Effective ◽  
Fenton’S Oxidation ◽  
Cost Effective Method ◽  
Optimum Ph ◽  
The Subject ◽  
The Cost ◽  
Fenton's Oxidation ◽  
Maximum Removal

The present study aims to establish the use of iron (Fe) from larerite in the case of Fenton's oxidation process which is a simple and cost-effective method for degradation of nitro compounds in effluents and in surface or ground water. 4-nitroaniline (4-NA) degradation by Fenton's oxidation method is the subject of the present study so as to optimize pH, hydrogen peroxide/iron (H/F) ratio at different initial concentrations of 4-NA. The optimum pH obtained was 3. The present study has also established optimum H/F ratio for the different initial concentrations of 4-NA for both conventional and use of Fe from laterite. The maximum removal efficiency of 99.84% was obtained for an H/F ratio of 100 for 0.5 mM initial concentration of 4-NA. The study establishes the use of Fe extracted from locally available laterite soil (LS) as a replacement of Fe salts so as to reduce the cost of the process.

scholarly journals Comparative Analysis of the Physicochemical Parameters of Breast Milk, Starter Infant Formulas and Commercial Cow Milks in Serbia

2016 ◽  
Vol 33 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Slavica Sunarić ◽  
Tatjana Jovanović ◽  
Ana Spasić ◽  
Marko Denić ◽  
Gordana Kocić
Keyword(s):  
Electrical Conductivity ◽  
Surface Tension ◽  
Refractive Index ◽  
Breast Milk ◽  
Human Milk ◽  
Physicochemical Parameters ◽  
Titratable Acidity ◽  
Cow Milk ◽  
Physical Parameters ◽  
Infant Formulas

Summary Data on the physical properties of cow milk and infant formulas are important since they indicate the differences in physicochemical and rheological characteristics and compatibility with natural breast milk. This fact is important not only for quality control but also for the use of these commercial products as infant diet supplements or as complete breast milk substitutes. This study was undertaken to determine refractive index, surface tension, pH, electrical conductivity, viscosity and titratable acidity of the UHT cow milk, starter infant formulas and breast milk of Serbian mothers in order to compare commercial milk formulations with natural human milk. The paper also presents the measured data of some physical parameters of human milk about which there is little information in the literature. It has been also demonstrated how these parameters were changed by freezing and prolonged storage of breast milk. In this study, 8 commercial cow milks, 6 starter infant formulas and 15 different samples of colostrum, transition and mature breast milk were included. The titratable acidity, pH, electrical conductivity, refractive index, viscosity and surface tension were measured by using standardized techniques. It has been found that infant formulas available on the Serbian market differ in physicochemical parameters compared to breast milk. Regarding these parameters, none of the analyzed formulas fully corresponded to breast milk. It has been also shown that measurement of physical parameters is simple and inexpensive way to monitor the milk shelf-life which is important for human milk banks.

Coagulation as Pretreatment of Food Industry Wastewater

1990 ◽  
Vol 22 (9) ◽  
pp. 1-8 ◽  
Author(s):  
B. Rusten ◽  
B. Eikebrokk ◽  
G. Thorvaldsen
Keyword(s):  
Process Design ◽  
Food Industry ◽  
Optimum Process ◽  
Chemical Agent ◽  
Chemical Pretreatment ◽  
Coagulation And Flocculation ◽  
Optimum Ph ◽  
Removal Efficiencies ◽  
Industry Wastewater ◽  
Maximum Removal

Jar-tests, pilot-plant and full-scale experiments on chemical pretreatment of food industry wastewater have been performed. The objectives were to find maximum removal efficiencies, suitable coagulation and flocculation agents, and the optimum process design. The results showed that the wastewater composition greatly influences the maximum removal efficiencies and also the conditions for optimum coagulation and flocculation. Optimum pH depends on the chemical agent and the actual dosage used. With proper pH-adjustment, addition of either 0.10-0.15 mg FeCl3-6H2O/mg COD, or about 0.20 mg Al2(SO4)3.18H2O/mg COD, was sufficient to obtain good removal of organic matter. Maximum removal efficiencies of 67-90 % total COD were achieved, depending on wastewater composition.

A bench-scale study on chromium recovery from tanning wastewater

1995 ◽  
Vol 31 (9) ◽  
pp. 73-81 ◽  
Author(s):  
Thongchai Panswad ◽  
Orathai Chavalparit ◽  
Yaowanud Sucharittham ◽  
Sasithorn Charoenwisedsin
Keyword(s):  
Sulfuric Acid ◽  
Magnesium Oxide ◽  
Settling Velocity ◽  
Chromium Concentration ◽  
The Other ◽  
Chrome Tanning ◽  
Optimum Ph ◽  
Different Types ◽  
Tanning Process ◽  
Chromium Recovery

In order to recover chromium, wastewaters from the chrome-tanning process in two Thai tanneries were coagulated with magnesium oxide or sodium carbonate at various dosages. Different types of polymer were also tried to improve the settleability of the chromium sludge which, in turn, was redissolved by sulfuric acid. The produced chromium III sulfate (Cr2(SO4)3) solution was sufficiently concentrated for direct reuse in the tanning step. The settling pattern of the chromium sludge was also observed and optimum sedimentation periods ranging from 1 to 17 hours were suggested. Under no tanning-additive (a chemical to improve chromium sorption onto hides) circumstances, the discharged wastewater contained 5-11 g Cr2O3/l and the most promising coagulant was MgO at a dose of twice the stoichiometric value and an optimum pH of 7-8. The resulting chromium precipitate or sludge was quite dense (21% solids) and possessed a good settling velocity (234 mm/h), making the decantation process very easy, whereas the corresponding acid requirement for the dissolution process was 1.5 times the stoichiometric value. On the other hand, in the tanning-additive situation, the chromium concentration in the drain was reduced to 3-6 g Cr2O3/l. Magnesium oxide was shown to be also the best coagulant but the dose was two times higher than that of the first circumstance, ie., four times that of stoichiometric requirement.

scholarly journals Assessment of Water Quality of Kolpu Khola in Sisdol Landfill Area of Nuwakot District

2015 ◽  
Vol 15 (1) ◽  
pp. 107-114
Author(s):  
Ujjwal Thapa Shrestha ◽  
Jaya K. Shrestha ◽  
Rohini P. Devkota
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Physicochemical Parameters ◽  
Rapid Change ◽  
Industrial Effluent ◽  
Total Hardness ◽  
Physical Parameters ◽  
Significance Level ◽  
The Impact

The present study was carried out to determine the impact of the leachate contamination on water quality of Kolpu Khola nearby Sisdol landfill site. Water samples were collected from six different sites of Kolpu Khola from upstream to downstream. The samples were collected in clean plastic bottles from a leachate collection from December, 2007 to August, 2008 and analyzed for the determination of physical parameters (pH, conductivity, temperature) and chemical parameters (dissolved oxygen, alkalinity, chloride, calcium hardness, total hardness, BOD5, PO4-P, NO3-N, NH4-N) using a standard method. It was found that leachate was severely polluted with most of the physicochemical parameters being higher than the generic standard for industrial effluent discharged into inland surface water. The variation of BOD and COD showed that the chemistry of the leachate in the landfill was undergoing rapid change. The surface water of Kolpu Khola was not polluted from chloride point of view and the spatial variation of chloride content was significant at 0.01 significance level. The river water at all the sites under study had PO4-P above natural range i.e. 0.005 to 0.020 mg/l and was not suitable for livestock drinking and for aquatic animals with reference to most of the physicochemical parameters studied.DOI: http://dx.doi.org/10.3126/njst.v15i1.12026Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 107-114

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