scholarly journals Treatment of Tannery Effluent by Locally Available Commercial Grade Lime

2012 ◽  
Vol 5 (1) ◽  
pp. 143-150 ◽  
Author(s):  
M. A. Sabur ◽  
M. M. Rahman ◽  
S. Safiullah
Keyword(s):  
Large Scale ◽  
Chromium Content ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Tannery Effluent ◽  
Total Chromium ◽  
Commercial Grade ◽  
Before And After

The treatment of tannery effluent was carried out based on the locally available commercial grade lime. Collected tannery effluent was acidic (pH 3.94) in nature with total chromium content, chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS) and the conductivity at 30°C were 987 mg/L, 3175.32 mg O2/L, 22915 mg/L, 13360 mg/L and 60.7 mS/cm, respectively. The effluent was treated by chemical precipitation method and the dependency on pH in the treatment was investigated by altering the pH from 6.0 to 11.0 by the gradual addition of lime slurry. The treated effluents were characterized primarily in terms of COD and conductivity and we obtained lowest COD (345 mg O2/L) and conductivity (21.4 mS/cm at 30°C) values at pH 9. Then a large scale treatment was carried out with 20.0 L of the effluent in the same experimental condition at pH 9 and the removal of chromium, COD, TSS, TDS and conductivity (at 30°C) were achieved up to 99.79, 60.99, 97.22, 98.27 and 41.85%, respectively. Chloride concentration was also measured before and after treatment but no significant change was observed. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.12557        J. Sci. Res. 5 (1), 143-150 (2013)

Chemical precipitation method for chromium removal and its recovery from tannery wastewater in Ethiopia

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Chromium Content ◽  
Chemical Precipitation ◽  
Tannery Wastewater ◽  
Precipitation Method ◽  
Tannery Effluent ◽  
Settling Rate ◽  
Flame Atomic Absorption ◽  
Significant Difference ◽  
Optimum Ph ◽  
Removal And Recovery

Most of the tanneries in Ethiopia (90%) do not treat and very few (10%) partially treat their effluent before discharging it into the receiving water bodies. The untreated tannery effluent causes tremendous pollution of water resources in the country, especially due to its high organic loading and chromium content. Chromium(III) salts are the most widely used chemicals for tanning processes, but only about 60-70% of total chromium salts reacts with the hides and about 30-40% of the chromium remain in the solids and liquid wastes (especially spent tanning solutions). Therefore, the removal and recovery of the chromium content of these wastewaters is necessary for environmental protection and economic reasons. The purpose of this study was to develop an alternative process for removing and recovering trivalent chromium from tannery wastewater via chemical precipitation with sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2) and magnesium oxide (MgO). The effects of pH, stirring time, settling rate and sludge volume were studied in batch experiments. Flame atomic absorption spectrometry was used to determine Cr concentration. The results showed that removal efficiencies of the precipitating agents NaOH (99.97%), Ca(OH)2 (99.97%) and MgO (99.98%) at optimum pH values were not significantly different. However, there was a significant difference in sludge volume of NaOH (590 mL), Ca(OH)2 (412 mL) and MgO (85 mL). The optimum pH of 9.8-10.3 with removal efficiency of 99.98% and the good sludge with high settling rate and lower volume was obtained using MgO precipitating agent. Hence the MgO was found to be a good precipitating agent for removal and recovery of chromium from tanning wastewater. The basic chromium sulfate (BCS) recovered at pH 2.8 is suitable for tanning mixed with fresh BCS from the market.

Modelling and optimisation of chitosan anchored titanium dioxide nano-adsorbent for dairy industry effluent treatment

2021 ◽  
Author(s):  
B.L. Dinesha ◽  
S. Hiregoudar ◽  
U. Nidoni ◽  
K.T. Ramappa ◽  
A.T. Dandekar ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Dairy Industry ◽  
Oxygen Demand ◽  
Chemical Precipitation ◽  
Effluent Treatment ◽  
Precipitation Method ◽  
Cubic Model ◽  
Industry Effluent ◽  
Quadratic Models ◽  
Nano Adsorbent

AbstractThe present study emphasised the efficiency of chitosan anchored titanium dioxide nano-adsorbent on dairy industry effluent treatment. Chitosan titanium dioxide nano-adsorbent was synthesised by using chemical precipitation method and characterised for its particle size, surface morphology and texture. A four-factor-three-level Box–Behnken design along with response surface methodology was used to optimise the adsorption process parameters. Linear, two factor interaction, quadratic and cubic model techniques were used to demonstrate the influence of each parameter and their interaction effects on the responses. The quadratic models derived from the experimental data were used to predict the maximum per cent reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD). The optimised treatment combination for maximum per cent reduction in BOD (90.48%) and COD (82.10%) was found to be initial concentration of 100 mg L−1, pH of 7, dosage of 1.25 mg L−1 and contact time of 100 min.

PREPARATION AND CHARACTERIZATION OF TiO2/SERICITE COMPOSITE MATERIAL WITH FAVORABLE PIGMENTS PROPERTIES

2019 ◽  
Vol 26 (08) ◽  
pp. 1950039 ◽  
Author(s):  
YU LIANG ◽  
WANTING CHEN ◽  
GUANG YANG ◽  
HAO DING ◽  
XIFENG HOU ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Scale Production ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Scale Production ◽  
Unique Method ◽  
The Cost

A unique method of preparing TiO2/sericite composite particles material was investigated by coating anatase TiO2 on the surface of sericite via chemical precipitation method. The results of X-ray diffraction, scanning electron microscope, infrared spectra and X-ray photoelectron spectroscopy indicated that TiO2 coated uniformly on the surface of sericite, and Si-O-Ti chemical bonds are formed during the thermal treatment process. The hiding power of Ti/SE-CPM composite is up to 85% of TiO2 white pigments, and the oil absorption value was equal to TiO2 white pigments. All these data demonstrated that the obtained Ti/SE-CPM samples have similar excellent properties compared with anatase TiO2 white pigments. Therefore, this study provides a feasible way of reducing the usage of TiO2 while maintaining similar pigment properties, which, of course, will reduce the cost, protect our environment and has a potential application in large-scale production of white pigments.

scholarly journals Treatment of Textile Wastewater by Coagulation Precipitation Method

2012 ◽  
Vol 4 (3) ◽  
pp. 623-633 ◽  
Author(s):  
M. A. Sabur ◽  
A. A. Khan ◽  
S. Safiullah
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Textile Wastewater ◽  
Quality Parameters ◽  
Precipitation Method ◽  
Alkaline Ph ◽  
Effluent Quality ◽  
The Individual ◽  
Influence Of Ph

Treatment of textile effluent, collected from Sattar Textile located at Chandra under Gazipur district, Bangladesh was carried out by chemical coagulation and precipitation method. The highly alkaline (pH=12.0) reddish orange colored effluent was characterized by chemical oxygen demand (COD) 1638 mg O2/L; total suspended solids (TSS) 9.76 g/L; total dissolved solids (TDS) 6.62 g/L and turbidly 31.24 FTU. In the present study, polyaluminium chloride (PAC) and SAFI (described in the results and discussions part) solutions were used as coagulants both individually and as their mixture at various ratios. As coagulation precipitation is highly pH sensitive, influence of pH was noted in each case. It was seen that the combined effect of both the coagulants is more effective than the individual effect of coagulants at a particular proportion at pH 6 for the removal of pollutional load from the effluent. The minimum dosages for the coagulants were worked out also from the initial beaker experiments. Finally, the effluent obtained from the large scale treatment was characterized for some effluent quality parameters and 90.17, 74.09 and 93.47% removal COD, TDS and turbidity were observed, respectively.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i3.10777 J. Sci. Res. 4 (3), 623-633 (2012)

scholarly journals Treatment of Tannery Effluent of Unit Bovine Hides’ Unhairing Liming by the Precipitation

2021 ◽  
Author(s):  
Anass Omor ◽  
Karima Elkarrach ◽  
Redouane Ouafi ◽  
Zakia Rais ◽  
Fatima-Zahra ElMadani ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Pathogenic Bacteria ◽  
Physicochemical Characterization ◽  
Chloride Concentration ◽  
Chemical Precipitation ◽  
Tannery Effluent ◽  
Chemical Agent ◽  
Tannery Effluents ◽  
Sulphide Ions ◽  
Aerobic Flora

The tannery effluents are characterized by high toxic pollutants such as sulfides; used in the tanning of animal’s skin. The mean objective of this work is the evaluation of the pollution degree of various operating units, and the treatment of tannery effluent generated from unhairing-liming unit. According to physicochemical characterization, this effluent was largely basic and very loaded in sulfides, which have harmful effects on human health and the environment as well. Otherwise, the microbiological characterization showed an absence of pathogenic bacteria and a low concentration of mesophilic aerobic flora, because of this effluent toxicity. Thus, the treatment of this effluent is indispensable before its reject into the environment. In fact, chemical precipitation is a promising approach for the treatment of this effluent. In this regard, ferric chloride was used as chemical agent to reduce and removal sulphide ions from this effluent. As result, this treatment gave an excellent abatement rate of sulphide, which reached more than 90% using a pH of 8.5 and a ferric chloride concentration of 1.4 mol/L.

Microwave Assisted ZnO Nanoparticles by Simple Precipitation Method: A Novel Approach

2020 ◽  
pp. 2150010
Author(s):  
Lalita D. Deshmukh
Keyword(s):  
Zno Nanoparticles ◽  
Large Scale ◽  
Ph Value ◽  
Aqueous Media ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Scale Production ◽  
Zno Nps ◽  
Time Saving ◽  
Vis Spectroscopy

Stated work consisted synthesis of ZnO nanoparticles (NPs) by the irradiation of microwaves. Material is formed by a simple chemical precipitation method by using Zinc Acetate Dehydrate (Zn(CH3COO)2[Formula: see text]2H2O) and Sodium hydroxide (NaOH) as base chemicals in aqueous media for two different pH (12 and 14) values. This synthesis was carried out at room temperature. Synthesized NPs are dried in Microwave oven for 3 min of duration each. X-ray Diffraction (XRD) study confirmed the trend of incremental crystallinity upon increasing pH. XRD reveals the existence of (100), (002), (101), (102) and (110) reflections at [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] two theta values, respectively. Crystallite size was determined by both Scherrer formula and W–H plot method. UV-Vis spectroscopy is utilized to probe the optical features of ZnO NPs. This confirms intrinsic excitonic transition properties of ZnO. UV absorbance shows decrement upon increasing pH value. Band gap depicts the decremental behavior upon increasing pH. Stated method is a novel and time saving method for ZnO NPs synthesis; a large scale production is also feasible by this method.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

Use of lime for the upgrading of existing wastewater treatment systems

1994 ◽  
Vol 29 (12) ◽  
pp. 279-282 ◽  
Author(s):  
C. Güldner ◽  
W. Hegemann ◽  
N. Peschen ◽  
K. Sölter
Keyword(s):  
Large Scale ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Fatty Acid Production ◽  
German States ◽  
Lime Solution ◽  
First Results ◽  
Pre Treatment

The integration of the chemical precipitation unit which would inject a lime solution into a series of mechanical-biological processes, including nitrification/denitrification, and the sludge treatment are the subject of this project. The essential target is the large-scale reconstruction of a mechanical-biological sewage treatment plant with insufficient cleaning performance in the new German states and the adjustment of the precipitation stage to the unsteady inflow of sewage. First results indicate that the pre-treatment performance could be improved by ≅ 20% and the discharge of concentrations of COD, BOD, N and P could be reduced and homogenized. In addition, experiments on hydrolysis and acidifiability of the pre-treatment sludge have been carried out on a laboratory level with the object of making sources of carbon readily available for denitrification. In the course of the experiment, inhibition of fatty acid production by calcareous primary sludge could not be detected. The characteristics of the sludge, such as draining and thickening were considerably improved by the adding of lime.

Tuning the mechanical and dielectric properties of zinc incorporated hydroxyapatite

2020 ◽  
Vol 16 ◽  
Author(s):  
Alliya Qamar ◽  
Rehana Zia ◽  
Madeeha Riaz
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bone Growth ◽  
Healing Process ◽  
Secondary Phase ◽  
Chemical Precipitation ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Low Frequencies ◽  
A Minor

Background: Hydroxyapatite is similar to bone mineral in chemical composition, has good biocompatibility with host tissue and bone. Objective: This work aims to tailor the mechanical and dielectric properties of hydroxyapatite with zinc sudstitution, to improve wearability of implant and accelerate the healing process. Method: Pure and zinc incorporated hydroxyapatite Ca10(PO4)6(OH)2 samples have been successfully prepared by means of the chemical precipitation method. Results: The results showed that hydroxyapatite(Hap) having hexagonal structure was the major phase identified in all the samples. It was found that secondary phase of β-tricalcium phosphate (β-TCP) formed due to addition of Zinc resulting in biphasic structure BCP (Hap + β-TCP). A minor phase of ZnO also formed for higher concentration of Zn (Zn ≥ 2mol%) doping. It was found that the Zn incorporation to Hap enhanced both mechanical and dielectric properties without altering the bioactive properties. The microhardness increased upto 0.87 GPa for Zn concentration equal to 1.5mol%, which is comparable to the human bone ~0.3 - 0.9 GPa. The dielectric properties evaluated in the study showed that 1.5 mol% Zn doped hydroxyapatite had highest dielectric constant. Higher values of dielectric constant at low frequencies signifies its importance in healing processes and bone growth due to polarization of the material under the influence of electric field. Conclusion: Sample Z1.5 having 1.5 mol% Zn doping showed the most optimized properties suitable for bone regeneration applications.

Sign in / Sign up

Export Citation Format

Share Document