scholarly journals Recovery Ion Hg2+ dari Limbah Cair Industri Penambangan Emas Rakyat dengan Metode Presipitasi Sulfida dan Hidroksida

2018 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Ilma Fadlilah ◽  
Agus Prasetya ◽  
Panut Mulyono
Keyword(s):  
Gold Mining ◽  
Mercury Level ◽  
Liquid Waste ◽  
Treatment Method ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Sulphide Precipitation ◽  
Slow Mixing ◽  
Precipitation Formation

Unlicensed gold mining activities (PETI) using mercury (Hg) as a gold element binder is called the amalgamation process. Mercury is a heavy metal toxic. The use of mercury can potentially cause pollution in environment, especially the aquatic environment. For overcoming the heavy metals mercury in liquid waste, it needs an alternative wastewater treatment method called chemical precipitation. This study is aimed to recover Hg2+ ions from liquid wastes by using sulphide precipitation and hydroxide methods. This research studied the effect of pH on Hg ions which is deposited in the precipitation process and found out the rate of Hg precipitation formation. Precipitation was done by using sodium sulphide (Na2S) 0.3 M and Ca(OH)2 0.004 M as a precipitation agent with rapid mixing speed for about 200 rpm for 3 minutes and continued with slow mixing for about 40 rpm for 30 minutes. Then, just let the liquid sample be for 24 hours to precipate the precipitate formed. The results show that precipitation method by using a Na2S solution can decrease the content of Hg in HgCl2 synthetic waste. An optimum  mass of HgS precipitate of  0,0458 g was achieved pH 9 for 200 mL of wastewater liquid with a removal efficiency percentage up to 99.81%. The concentration of mercury can be derived from 130 ppm to 0.25 ppm. The rate of formation of HgS precipitate was obtained 0.0004g/ hour. While, hydroxide precipitation method can decrease mercury level up to 90,11% at pH 12 and mass of Hg (OH)2 precipitate obtained is 0,2784 g. However, the result of EDX analysis of the precipitate of Hg (OH)2 shows that the content of Hg precipitate is just 0.281%.

scholarly journals Microwave sintering of nano size powder β-TCP bioceramics

2014 ◽  
Vol 46 (2) ◽  
pp. 185-193 ◽  
Author(s):  
B. Mirhadi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tricalcium Phosphate ◽  
Microwave Sintering ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Grain Size ◽  
Nano Size

A nano sized beta tricalcium phosphate (?-TCP) powder was conventional sintered (CS) and microwave sintered (MW), in order to obtain dense ?-TCP ceramics. In this work the effect of microwave sintering conditions on the microstructure, phase composition and mechanical properties of materials based on tricalcium phosphate (TCP) was investigated by SEM (scanning electron microscopy)and XRD(X-ray diffraction) and then compared with conventional sintered samples. Nano-size ?-TCP powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of submicrometre ?-TCP powder in situ. The ?-TCP samples microwave (MW) sintered for 15 min at 1100?C, with average grain size of 3?m, showed better densification, higher density and certainly higher hardness than samples conventionally sintered for 2 h at the same temperature. By comparing sintered and MW sintered ?-TCP samples, it was concluded that MW sintered ?-TCP samples have superior mechanical properties.

Photocatalytic Activity of Gd3+ and Sm3+ Co-Doped BiVO4 Powders Prepared by Chemical Precipitation Process

2012 ◽  
Vol 508 ◽  
pp. 259-262 ◽  
Author(s):  
Cheng Zhi Jiang ◽  
Rui Yang ◽  
Sen Bai ◽  
Xu Dong Lu
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Co Doped

Pure BiVO4, single doped and co-doped BiVO4 have been prepared by chemical precipitation method and characterized by the techniques such as XRD and SEM/EDAX. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate pure BiVO4, single doped BiVO4 and co-doped BiVO4 photocatalytic activity. The results show that doping of single doped and co-doped significantly enhance the photocatalytic activity of BiVO4. When the 0.1%Gd3+ and 0.2%Sm co-doped, the BiVO4 degradation rate reaches 91%.

scholarly journals Chemical Precipitation method for Sulphate Removal from Treated Wastewater of Al-Doura Refinery

2021 ◽  
Vol 39 (3A) ◽  
pp. 338-354
Author(s):  
Rana M. Rashedd ◽  
Aumar Alnakeeb
Keyword(s):  
Wastewater Treatment ◽  
Mixing Time ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Treated Wastewater ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Maximum ◽  
Rate Maximum ◽  
Sulphate Removal

Wastewater treatment by Wastewater Treatment Plant, named (INGECO) in Doura refinery suffers from the elevated level of sulphate ion concentrations compared to the recommended EPA [14] specified (250 mg/L). The annual rate, maximum and peak sulphate concentrations that found to be 360; 425 and 550 mg/L respectively. In this study samples prepared from industrial wastewater and the average, maximum and peak sulphate concentrations to be used in chemical precipitation process by using BaCl2 or Al(OH)3. Results obtained from BaCl2 treatment refer to the optimum (dosage, mixing time and mixing speed) to be used in sulphate removal for reuse purpose were (1.5 g/L, 1.2 hr and 80 rpm), (2.25 g/L, 1.5 hr and 90 rpm) and (3.0 g/L, 2 hr and 90 rpm) for each of average, maximum and peak concentrations respectively. Whereas for disposal purpose, were (0.36 g/L, 15 min and 100 rpm), (1.1 g/L, 15 min and 70 rpm), (1.72 g/L, 15 min and 90 rpm) respectively. This process was achieving of highly sulphate removal, but expensive. Whereas the results obtained by using Al(OH)3 indicated unsuitability for treated refinery wastewater treatment of low sulphate concentrations and neutral pH.

Densification and Hardness Behaviour of Nanocrystalline Hydroxyapatite/β-Tricalcium Phosphate Composite Powders

2012 ◽  
Vol 14 ◽  
pp. 81-91 ◽  
Author(s):  
Behzad Mehdikhani ◽  
Bahman Mirhadi
Keyword(s):  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Composite Powders ◽  
Fine Grained ◽  
Nanocrystalline Hydroxyapatite ◽  
Average Grain Size ◽  
Ammonium Hydrogen ◽  
Sample Characterization

In this study, dense, fine-grained biphasic calcium phosphate bioceramics were designed via sintering method. nanosize hydroxyapatite / β-tricalcium (HA/β-TCP) phosphate powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and di-ammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of sub-micrometre HA/β-TCP powder in situ. The sinterability of the nanosize powders, and the microstructure, mechanical strength of the prepared HA/β-TCP bioceramics were investigated. Bioceramic sample characterization was achieved by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and density measurements. Powders compacted and sintered at 800, 900, 1000 and 1100°C showed an increase in relative density from 57% to 93%. The results revealed that the maximum hardness of 229 HVwas obtained for HA/β-TCP sintered at 1100°C.

Photocatalytic Activity of Sm-Doped BiVO4 Powders Prepared by Chemical Precipitation Process

2011 ◽  
Vol 391-392 ◽  
pp. 1283-1286
Author(s):  
Cheng Zhi Jiang ◽  
Xu Dong Lu ◽  
Yan Qiu Tan ◽  
Sen Bai
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Chemical Precipitation ◽  
Nano Particles ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
Precipitation Process

Pure BiVO4, Sm doped BiVO4have been prepared by chemical precipitation method and characterized by the techniques such as XRD and SEM. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate pure BiVO4, Sm doped BiVO4photocatalytic activity. The results show that doping of Sm decreases the diameter of BiVO4 nano-particles and significantly enhance the photocatalytic activity of BiVO4. When the 0.2% Sm doped, the BiVO4degradation rate reaches 92.8%.

Assessment of the Chemical Precipitation Process as a New Approach for Industrial Emission Abatement Systems

2018 ◽  
pp. 30-43
Author(s):  
Ahmet Ozan Gezerman ◽  
Burcu Didem Çorbacıoğlu
Keyword(s):  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Industrial Scale ◽  
Precipitation Method ◽  
Precipitation Process ◽  
New Approach ◽  
Industrial Emission ◽  
Emission Abatement ◽  
Comparative Advantages

The abatement of emission gases, such as SOx, NOx, and COx, is one of the main problems studied by researchers for continuous developments, necessitating considerable investments by several industries. Currently, the scrubber system with its use form, and the chemical precipitation method that is considered as an alternative, are the two different processes that have demonstrated the best results for emission abatement. In this chapter, an assessment is performed on an industrial scale for both the processes, their comparative advantages are discussed, and possible applications presented.

scholarly journals Densification and Mechanical Behavior of β-Tricalcium Phosphate Bioceramics

2014 ◽  
Vol 36 ◽  
pp. 37-49 ◽  
Author(s):  
Behzad Mehdikhani ◽  
Gholam Hossein Borhani
Keyword(s):  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Average Grain Size ◽  
Ammonium Hydrogen ◽  
Sample Characterization ◽  
Nano Size

Nano-size β-tricalcium phosphate powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and di-ammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of sub-micrometre β-TCP powder in situ. The sinterability of the nano-size powders, and the microstructure, mechanical strength of the prepared β-TCP bioceramics were investigated. Bioceramic sample characterization was achieved by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and density measurements. Powders compacted and sintered at 800, 900, 1000 and 1100 °C showed an increase in relative density from 70 % to 93 %. The results revealed that the maximum hardness of 240 H was obtained for β-TCP sintered at 1100 °C.

Performance Stability of Small Biological Chemical Treatment Plants

1990 ◽  
Vol 22 (3-4) ◽  
pp. 275-282
Author(s):  
R. Storhaug
Keyword(s):  
Activated Sludge ◽  
Chemical Treatment ◽  
Chemical Precipitation ◽  
Poor Quality ◽  
Precipitation Process ◽  
Chemical Plants ◽  
Effluent Standards ◽  
Main Portion ◽  
Rotating Biological Contactors ◽  
Number Of Treatment

Biological and chemical treatment plants constitute a main portion of the overall number of treatment plants in Norway. The biological and chemical plants are divided into three process groups, simultaneous precipitation and activated sludge, combined precipitation and rotating biological contactors (RBC) and post precipitation and activated sludge. Aluminium sulphate or ferric chloride are the commonly used flocculants in the chemical precipitation process. Effluent data from 174 Norwegian biological chemical treatment plants are evaluated. Compared to the effluent standards for each process group, post precipitation shows the best performance. On an average these plants have the lowest actual utilization of the design capacity. The most important factors that cause the treatment plants not to meet the effluent standards are, poor quality of the sewer system, improper design of the plant and organizational problems. Satisfactory separation of particles, flow equalization and proper operational management, are the basic demands to achieve low effluent concentrations for tot-P and BOD7.

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.

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