scholarly journals Removal of cyanide from alumina smelter wastewater using precipitation and filtration technique

2021 ◽  
Vol 896 (1) ◽  
pp. 012075
Author(s):  
M F Huda ◽  
Q Helmy

Abstract Aluminum is a metal that is used in many products because of its good conducting properties. However, in the production process, aluminum is not obtained easily but through a long process. In aluminum smelting process, wastewater that is produced indicates the existence of pollutants as determined by several indicators of water pollution, one of which is cyanide that will threaten human and environmental health if not treated properly. This study was conducted to determine the optimal dose of ferrous sulfate to remove cyanide, the precipitation and filtration process efficiency in reducing cyanide, and its effect on pH of wastewater. Data were collected from an aluminum smelting company, and experiments were conducted in the laboratory. Based on results, ferrous sulfate dose of 93 mg/l is the most optimal dose in removing cyanide with an efficiency of 58.74±0.51%, while filtration process provides an efficiency of 81.65±0.42%. Precipitation with ferrous sulfate makes pH value of wastewater decrease, but filtration process increases the value again. Throughout the whole process, cyanide can be reduced by a combination of precipitation and filtration process with the efficiency of 92.43±0.26% and an average final effluent concentration of 0.78 mg/L from an initial concentration of 10.3 mg/L.

Teknik ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 78 ◽  
Author(s):  
Arya Rezagama ◽  
Mochtar Hadiwidodo ◽  
Purwono Purwono ◽  
Nurul Fajri Ramadhani ◽  
Mia Yustika

Air lindi yang meresap ke dalam tanah yang berpotensi bercampur dengan air tanah sehingga menimbulkan pencemaran tanah, air tanah dan air permukaan. Komposisi limbah lindi dari berbagai TPA berbeda-beda bergantung pada musim, jenis limbah, umur TPA. Proses dalam TPA menghasilkan molekul organik recalcitrant yang ditunjukkan dengan rendahnya rasio BOD/COD dan tingginya nilai NH3-N. Belum optimalnya pengolahan air lindi di Jatibarang membutuhkan pretreatment sebagai bentuk upaya alternatif dalam proses pengolahan air lindi sebelum masuk ke dalam proses aerated lagun. Penelitian ini bertujuan untuk menganalisa pengaruh koagulan kimia pada penyisihan bahan organik air lindi TPA Jatibarang. Penelitian dilakukan pada bulan April- Agustus 2016. Karaktersitik air lindi TPA Jatibarang termasuk dalam kategori "moderately stable" dan lindi muda. Penyisihan bahan organik dengan menggunakan kuagulan kimia FeCl3 dan Al2SO4 menunjukkan nilai yang cukup signifikan untuk parameter COD, BOD, TSS. Penggunaan dosis optimal terjadi pada 16 g/L FeCl3 serta 16 g/L Al2SO4 dapat menurunkan nilai COD sebesar 51% dan 65%, BOD sebesar 50% dan 56%, dan TSS sebesar 24% dan 21%. Perubahan nilai pH akibat penambahan koagulan berpengaruh positif terhadap tingkat penyisihan, namun memberikan dampak negatif yaitu buih yang cukup banyak. Penurunan beban organik menguntungkan bagi sistem pengolahan lindi eksisting TPA Jatibarang. [Title: Removal of Lindi Water Organic Waste of TPA Jatibarang using Chemical Coagulation- Floculation] Leachate grounding into the soil that potentially could mix with the groundwater caused contamination of soil, groundwater and surface water. The composition of waste landfill leachate from the various location is depending on the season, the type of waste, and landfill age. Process in the TPA produces recalcitrant organic molecules as indicated by the low ratio of BOD/COD and NH3-N high value. The ineffective treatment of leachate at Jatibarang require a pretreatment as a form of alternative effort in the processing of leachate prior to entry into the aerated lagoon process. This study aims to analyze the influence of chemical coagulants on grounding organic material Jatibarang landfill leachate. The study was conducted in April-August 2016. Jatibarang landfill leachate characteristics were categorized as "moderately stable" and young leachate. Allowance for organic materials using chemical coagulants of FeCl3 and Al2SO4 showed significant values for the parameters of COD, BOD, and TSS. The use of optimal dose occurs at 16 g/L FeCl3 and 16 g/L Al2SO4 which can reduce the COD value by 51% and 65%, BOD by 50% and 56%, and TSS at 24% and 21%. PH value changes due to the addition of coagulant positive effect on the level of the allowance, but a negative effect that is quite a lot of froth. The decline in organic load favorable for existing landfill leachate treatment systems Jatibarang. 


Author(s):  
R. F. Sabirov ◽  
A. F. Makhotkin ◽  
Yu. N. Sakharov ◽  
I. A. Makhotkin ◽  
I. Yu. Sakharov

Experimental studies of the kinetics and mechanism of the process, decomposition of apatite by phosphoric acid, in the Apatite-H3PO4-H2O system without the addition of sulfuric acid have been performed. The study of the decomposition process of Kovdorsky apatite with certain particle sizes was carried out in a batch reactor with a volume of 1 dm3 with stirring of the reaction mixture, and an initial concentration of phosphoric acid of 17% by weight, at a temperature of 78–82 °C. Observation of the process was carried out by determining the concentration of phosphoric acid and the concentration of monocalcium phosphate. The acidity of the reaction mixture was determined by the pH meter readings (pH-105 MA with a glass combined-ESC-10603 electrode). It was shown that during the whole process a constant smooth increase in the pH value of the reaction mixture to pH 6 occurs. Comparison of the pH values of the reaction mixture during the actual at the time of determining the concentration of phosphoric acid and pH of phosphoric acid of the corresponding concentration in the aqueous solution shows that the pH value of the reaction mixture is significantly affected by the presence of monocalcium phosphate gel. During the process, during the first thirty minutes, the concentration of phosphoric acid decreases from 17 to 10% by weight, the corresponding quantitative formation of monocalcium phosphate gel and a proportional increase in the pH of the reaction mixture. Then, as the concentration of phosphoric acid decreases, the process slows down and does not proceed to the end under the experimental conditions. The dependence of the concentration of hydrogen ions in the reaction mixture on the time of the process of decomposition of apatite in phosphoric acid, which is presented in logarithmic coordinates, shows that the mechanism of formation of hydrogen ions during the whole process does not change. Thus, it is shown that the process of decomposition of apatite by phosphoric acid in the Apatite-H3PO4-H2O system proceeds with the formation of an intermediate product - monocalcium phosphate gel. When this occurs, a corresponding significant change in the pH values of the reaction mixture occurs. During the whole process there is a constant decrease in the concentration of phosphoric acid.


JOM ◽  
2011 ◽  
Vol 63 (8) ◽  
pp. 120-126
Author(s):  
Yashuang Gao ◽  
Mark P. Taylor ◽  
John J. J. Chen ◽  
Michael J. Hautus

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 82 ◽  
Author(s):  
Aijia Chen ◽  
Xiaodong Hao ◽  
Yunhua Xiao ◽  
Kai Zou ◽  
Hongwei Liu ◽  
...  

Acidithiobacillus thiooxidans A01 is widely used in bioleaching processes and commonly thrives in most metal-rich environments. However, interactions between different heavy metals remain obscure. In this study, we elaborated the effect of ferric iron on the growth and gene expression of At. thiooxidans A01 under the stress of nickel. The results showed that 600 mM Ni2+ completely inhibited the growth and sulfur metabolism of At. thiooxidans A01. However, trace amounts of Fe3+ (0.5 mM) facilitated the growth of At. thiooxidans A01 in the presence of 600 mM Ni2+. With the addition of 5 mM Fe3+, the maximum cell density reached 1.84 × 108 cell/mL, and pH value was 0.95. In addition, metal resistance-related and sulfur metabolism genes were significantly up regulated with extra ferric iron. Taking the whole process into account, the promoting effect of Fe3+ addition can be attributed to the following: (1) alleviation of the effects of Ni2+ toxicity and restoring the growth of At. thiooxidans A01, (2) a choice of multiple pathways to export nickel ion and producing precursor of chelators of heavy metals. This can suggest that microorganisms may widely exhibit metabolic activity in iron-rich environments with heavy metals. Our study will facilitate the technique development for the processing of ore bodies with highly challenging ore compositions.


2011 ◽  
Vol 695 ◽  
pp. 13-16
Author(s):  
Xuan Liang ◽  
Xue Gang Luo ◽  
Xiao Yan Lin

Expansion-treated rice husk (ERH) had been used as adsorbent for removing copper(II) ions, and showed strong adsorption ability and removal efficiency for copper(II) ions. In this paper, the surface and bulk structures of ERH adsorbent were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM), ERH was treated by water solution with different pH value, and the adsorption performance of ERH for copper(II) ions was investigated through adsorption static experiments in order to study the adsorption mechanism. The result showed that ERH treated by alkaline solution had high removal efficiency for copper(II) ions, the reason ascribed to the large surface area of ERH. ERH had competitive adsorption for H+ and Cu2+, and a monolayer adsorption process played an important role in the whole process.


2016 ◽  
Vol 87 (17) ◽  
pp. 2066-2075 ◽  
Author(s):  
ZH Zhang ◽  
ZQ Xu ◽  
XX Huang ◽  
XM Tao

This paper reports an investigation of dyeing processes of textiles made from a novel 100% bio-based and fully degradable polylactide/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fiber. The dye exhaustion, depth of shade and fastness, as well as bursting strength of dyed PLA/PHBV fabrics have been evaluated in terms of types and concentration of dyestuff, dyeing bath temperature, duration, liquor ratio and pH value. Finally, the energy cost of the whole dyeing process of the proposed material is calculated and compared with that of polyethylene terephthalate. The experimental results show that an excellent dyeing effect and bursting strength can be achieved by properly applied dyes (e.g. C.I. Disperse Orange 30, Red 74, and Blue 79) under optimal low-dyeing-temperature conditions (100℃, 10 min, pH 5, LR 30:1). In addition, considering the low energy cost during the whole process, PLA/PHBV fibers can be regarded as a promising and environment-friendly material for the textile industry.


Author(s):  
Augustine Chioma Affam

This study was conducted to investigate the removal of COD, BOD, turbidity and colour from leachate using vertical upflow filtration technique. Limestone media with a density of 2554kg/m3 was crushed and graded in sizes of 4-8 mm, 8-12 mm and 12-18 mm. Trial runs were done before the main experiment at an interval of 24 h analysis. Leachate was between pH 7.94 to 8.12 before experiments but increased to pH 8.42 after the filtration process. Maximum headloss at steady flow rate 20mL/min was 0.5 cm. The optimum treatment was achieved with 4 – 8 mm, 8 – 12 mm & 12 – 18 mm media size in combination and removal efficiency was 22 to 81 %, 22 to 75 %, 32 to 86 %, and 36 to 62 % for BOD, COD, turbidity and colour respectively. Vertical upflow roughing filter can be used for pre-treatment of leachate before further treatment.


2020 ◽  
Vol 4 (2) ◽  
pp. 85-94
Author(s):  
Nila Puspita Sari ◽  
Mashuri Mashuri

Peat water can cause diseases such as cholera, hepatitis, dysentery, skin and eye diseases, and digestive diseases. Peat water is source water that is used daily needed by society in Segomeng. Mangrove wood is a material that can be used in the process of water purification because it can be used as activated charcoal which is a carbon compound, which is produced from a material that contains carbon. The research purpose is to know whether activated carbon of mangrove wood charcoal can be a medium of peat water filtering into clean water. This research type is the experiment and the design of this research uses Complete Random Design with some treatment which is arranged randomly for all experimental units. The different treatments are given, among others, using slow sand filtration and clay soil as a coagulant, using a slow sand filter with activated charcoal added mangrove wood with a thickness of 10 cm, and with a thickness of 15 cm. The results showed filtration with the addition of activated charcoal from mangrove wood with a thickness of 15 cm in getting the best results, can increase the pH value and is expected to improve the water quality of the acidic, odor-free, reducing taste, and the rapid filtration process that is 10 minutes. The conclusion is that the addition of activated carbon from mangrove wood charcoal is quite effective in the process of peat water filtration and can improve physical quality of water. The Suggestion is,should be measured of physical, chemical and biological character of peat water before and after filtration process.and also measurement of absorption of activated carbon of charcoal of mangrove wood before used as absorbent in filtration process


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