Studies on Pre-Treatment of Wastewater Containing Nitroaromatic Compound by Ultrasonic Cavitation

2012 ◽  
Vol 518-523 ◽  
pp. 2213-2217 ◽  
Author(s):  
Jiang Yue Tan
Keyword(s):  
Treatment Effect ◽  
Ph Value ◽  
Removal Rate ◽  
Ultrasonic Cavitation ◽  
Ultrasonic Power ◽  
Nitroaromatic Compound ◽  
Biochemical Processes ◽  
Improve Treatment ◽  
Initial Ph ◽  
Pre Treatment

In this paper, ultrasonic cavitation degradation was applied to treat the wastewater containing nitroaromatic compound. The factors influence to treatment effect such as the ultrasonic power and frequency, the wastewater initial pH value, were investigated by experiment. The experimental results showed that air-blasting in ultrasonic cavitation treatment could effectively improve treatment effect. The wastewater（COD:2650 mg•L-1,BOD5:240 mg•L-1，p-nitroaniline：490 mg•L-1，nitrobenzene:100 mg•L-1）was treated by ultrasonic cavitation degradation, the removal rate of p-nitroaniline,nitrobenzene and COD could be reached 91.3%,90.6% and 83.9% respectively after 3h. Biodegradability of the wastewater (B/C ratio ) can be increased to 0.4 , which satisfied the requirement for the subsequent biochemical processes.

The pretreatment of acrylonitrile and styrene with the ozonation process

1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu
Keyword(s):  
Organic Nitrogen ◽  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Acrylonitrile Butadiene Styrene ◽  
Ozone Treatment ◽  
Oxidation Reduction ◽  
Initial Ph ◽  
Cod Removal Rate ◽  
Ozonation Process

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.

Effect of Environment Factors on Phosphorus Removal Efficiency of Phosphate Reduction System

2011 ◽  
Vol 255-260 ◽  
pp. 2797-2801
Author(s):  
Chen Yao ◽  
Chun Juan Gan ◽  
Jian Zhou
Keyword(s):  
Removal Efficiency ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Removal Rate ◽  
Mass Rearing ◽  
Phosphate Removal ◽  
Environment Factors ◽  
Reduction System ◽  
Initial Ph ◽  
The Impact

Effect of environment factors such as initial pH value, dissolved oxygen (DO) and temperature on phosphorus removal efficiency of phosphate reduction system was discussed in treating pickled mustard tube wastewater. Results indicate that environment factors have significant influence on dephosphorization efficiency. And, the impact of DO on phosphate reduction is mainly by affecting the distribution of micro-environment inner biofilm, manifest as phosphate removal rate decreased with a fall in DO concentration, while overhigh DO can lead to detachment of biofilm, thus causing the increase of effluent COD concentration, and so DO need to be controlled in the range of 6 mg/L. Moreover, a higher temperature is more beneficial to phosphorus removal by PRB. Unfortunately, exorbitant temperature can result in mass rearing of Leuconostoc characterized with poor flocculability in reactor, and that cause turbidity in effluent appeared as a rise in COD of effluent. Hence, the optimal temperature is found to be about 30°C.

The Treatment of Acid Copper-Containing Wastewater by Eggshell-Flyash System

2011 ◽  
Vol 183-185 ◽  
pp. 967-970
Author(s):  
Tao Liu
Keyword(s):  
Heavy Metal ◽  
Calcination Temperature ◽  
Removal Efficiency ◽  
Treatment Effect ◽  
Ph Value ◽  
Removal Rate ◽  
Good Treatment ◽  
Egg Shells ◽  
Egg Shell ◽  
Application Prospects

Removal efficiency of heavy metal Cu from acid wastewater using egg shell as adsorbent was investigated. The influence of calcination temperature and dosage of egg shell, as well as pH value on the removal efficiency were discussed to obtain the optimum removal condition. The results show that the removal rate of lead would achieve the best result of 99.56% when we use the egg shells calcined at 400°C,2h, and the content of egg shells is 30g/L, pH=3.0.Using eggshells to treat acid chrome-containing wastewater is simple and easy to be operated, which has application prospects for the process and good treatment effect.

scholarly journals Application Of Seeding Crystallization as a Pre-Treatment Stage for The Reduction of Scaling Tendency of Seawater Feed to Thermal Desalination Units

2021 ◽  
Vol 15 (1) ◽  
pp. 10-17
Author(s):  
Mazen N. Al-Amaireh
Keyword(s):  
Kinetic Parameters ◽  
Growth Kinetic ◽  
Growth Process ◽  
Ph Value ◽  
Operating Conditions ◽  
Integration Step ◽  
Surface Integration ◽  
Thermal Desalination ◽  
Initial Ph ◽  
Pre Treatment

Objective: The fouling inhibition in seawater desalination and scale control using crystallization with calcite seeds is evaluated experimentally in this study. Methods: The growth kinetic parameters are determined experimentally, correlated and discussed at different operating conditions. Supersaturation levels represent driving force behind the growth of crystals, which is influenced directly by seawater pH values and temperatures. Results: Results indicate that the initial pH value of seawater must be controlled to be in the range (8-9) and calcite seeds will not have the potential to start the growth process in seawater at the normal pH (7.36). The growth kinetic parameters are determined from the measured desupersaturation curves. Conclusion: It is found that the growth process of calcite is controlled by the surface integration step. The growth rate of calcite increases with increasing temperature and seeding ratio (up to 1 g/L), while it decreases with increasing the salinity of seawater.

scholarly journals Treatment of By-Products Generated from Anaerobic Digestion of Municipal Solid Waste

2019 ◽  
Vol 11 (9) ◽  
pp. 4933-4940 ◽  
Author(s):  
Przemysław Seruga ◽  
Małgorzata Krzywonos ◽  
Marta Wilk
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Ph Value ◽  
Pilot Scale ◽  
Air Stripping ◽  
Liquid Digestate ◽  
Initial Ph ◽  
Pre Treatment ◽  
By Products

Abstract Purpose This study aimed to examine the possibilities of the treatment of the by-products generated in the anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW): oxygen stabilization (composting) of the solid digestate and pretreatment with air stripping of the effluents (liquid digestate and leachate from maturation field and reactors from composting). Methods Oxygen stabilization (OS) was performed in full-scale in a mechanical–biological treatment (MBT) plant using three different methods, using an open field or enclosed box reactor with aeration. The ammonia stripping was performed in a pilot-scale installation using effluents from AD (liquid digestate) and OS (leachate from maturation field and reactors). Results The lowest self-heating possibility after the OS was recorded at 28.5 °C, which proves that the most stabilized was the sample after processing with structuring material addition. Due to air stripping, the highest efficiency of ammonium ions removal was noted at the level of 50.6%, with an initial pH value of 10.5, after 12 h. Among the examined factors pH value was found to be significant [the determination coefficient (R2) of 0.93]. Conclusions The oxygen stabilization of the digestate requires the structuring material addition before being placed in the reactor with aeration. The inert fraction from the ballistic separation of the OFMSW can be an interesting solution, as required structuring material. Air stripping as the effluents pre-treatment step can meet the MBT plants expectations. Graphic Abstract

Synthesis and Characterization of Zeolite X Obtained from Coal Gangue for Adsorption of Cu2+

2021 ◽  
Vol 13 (8) ◽  
pp. 1512-1520
Author(s):  
MiaoSen Zhang ◽  
SiYang Wang ◽  
Zheng Hu ◽  
RunZe Zhang ◽  
XiaoLi Wang
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Ph Value ◽  
Copper Ions ◽  
Removal Rate ◽  
Coal Gangue ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Zeolite X ◽  
Initial Ph

China is a big coal producing country, there are a lot of coal gangue piled up. The zeolite X was synthesized by alkali melting and hydrothermal method based on the coal gangue from Chifeng city, Inner Mongolia. The obtained zeolite X sample is characterized by X-ray diffraction, SEM, EDS spectrum and IR which showed the X zeolite is an octahedral structure with complete crystal shape and uniform grain size. The results of BET showed the specific surface area of zeolite X is 354.8 m2/g and the minimum pore size is 3.8 nm which indicated that the zeolite X belongs to mesoporous materials. The adsorption conditions of the zeolite X adsorbent on copper ions were optimized. A solution containing Cu2+ ions with an initial concentration of 300 mg/L was added to the zeolite X with a dosage of 0.1 g and the initial pH value of the solution was adjusted to 6. Then the solution was oscillated for 120 min at 225 r/min. The maximum adsorption capacity and removal rate were 148.6 mg/g and 99.1%, respectively. The adsorption mechanism was discussed by adsorption kinetics and thermodynamics. The quasi-second order kinetic equation can be well used to describe the adsorption kinetics of zeolite X to Cu2+ (R2 = 0.9994) and Langmuir can well describe the adsorption behavior of zeolite X to Cu2+ (R2 = 0.9995) which showed the adsorption is a monolayer of chemical adsorption. The adsorption capacity of zeolite X to Cu2+ is about 4.0 times that of coal gangue, indicating that the zeolite X has good adsorption capacity.

Characteristics of Cu2+ Adsorption by Modified Rice Straw

2013 ◽  
Vol 726-731 ◽  
pp. 2622-2628
Author(s):  
Ming Da Liu ◽  
Lei Guo ◽  
Jun Yang ◽  
Yao Jing Wang
Keyword(s):  
Rice Straw ◽  
Ph Value ◽  
Removal Rate ◽  
Maximum Adsorption Capacity ◽  
Static State ◽  
Metal Biosorption ◽  
Initial Ph ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Sorption Time

In this paper, modified rice straw was investigated for its Cu2+removal ability from aqueous solution. The effects of environmental factors on metal biosorption were studied under static state, including initial concentration of metal ions, sorption time, initial pH value and adsordent dosage. In addition, the relevant equilibrium, kinetics were discussed. The results showed that the rice straw which was modified by NaOH had been improved greatly in its Cu2+removal ability. The rice straw had good effects on adsorption of low concentration of Cu2+solution. The adsorption data fit Langmuir isotherm model well, the maximum adsorption capacity for Cu2+reached 8.48 mg·g-1. The adsorption of Cu2+on the modified rice straw was a very rapid process, the kinetics fit a pseudo-second-order equation well. The pH value had prominent effect on the removal rate of Cu2+, adsorption efficient could reach over 92% when pH value was between 5 and 6.5. With increasing adsordent dosage, the removal rate of Cu2+increased.

Hydroquinone Wastewater Treatment by Means of Electrochemical Oxidation in Three-Dimensional Bipolar Cell

2012 ◽  
Vol 518-523 ◽  
pp. 2539-2542 ◽  
Author(s):  
Jun Sheng Hu ◽  
Jia Li Dong ◽  
Ying Wang ◽  
Lei Guan ◽  
Ying Yong Duan
Keyword(s):  
Electrochemical Oxidation ◽  
Oxidation Process ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Removal Rate ◽  
Supporting Electrolyte ◽  
Three Dimensional ◽  
Initial Ph ◽  
Single Factor Analysis ◽  
Dimensional Cell

By the static experiment, we studied the electrochemical oxidation process of simulated hydroquinone wastewater (concentration for 300mg•L-1) in the three-dimensional cell. Experimental inspected how various factors of the packing quality ratio, electrolysis voltage, supporting electrolyte concentration, and the initial pH value influence the effect of the removal of hydroquinone and CODCr. The results of the experiment clearly indicated with the increase of voltage applied the removal rate of hydroquinone and CODCr increased first and then decreased, finally and increased again. In the weak alkali conditions (pH=8.5), the removal rate of hydroquinone and CODCr is the highest, Electrolyte concentration and packing quality ratio to the effect of hydroquinone by electrochemical degradation is the larger. The results of the single factor analysis show that the most suitable processing conditions of simulated hydroquinone wastewater by bipolar electrocatalysis oxidation are the Na2SO4 concentration of 0.03mol•L-1, the electrolytic voltage of 6V, the initial pH value of 8.5, the packing quality ratio of 1:2. With this condition processing 3h, the removal rate of hydroquinone and CODCr reached 83.96% and 39.9%, respectively.

Ultrasound Enhanced Coagulation to Remove Organic Matter in Low Temperature and Low Turbidity Studies

2011 ◽  
Vol 356-360 ◽  
pp. 291-297 ◽  
Author(s):  
Jun Wen Li ◽  
Xin Li ◽  
Xiao Hui Xu ◽  
Dong Bing Wang
Keyword(s):  
Organic Matter ◽  
Low Temperature ◽  
Water Samples ◽  
Ph Value ◽  
Removal Rate ◽  
Experimental Results ◽  
Ultrasonic Power ◽  
Organic Matters ◽  
Enhanced Coagulation ◽  
Cod Removal Rate

In the experiment that the disposal of low temperature and low turbidity water, we observed the influence of some factors ,such as the acting time of ultrasound, ultrasonic power, amount of coagulant and the PH value of system, in disposing the organic matters of low temperature and low turbidity water. The experimental results show that the water samples which were disposed by ultrasound acting firstly and then by coagulation precipitate processing are best. When ultrasonic acting is 9 min, ultrasonic power transferred to 25 W, the amount of coagulant polyferric sulphate is 12 mg/L and the system pH is 7, the maximum of COD removal rate will up to 87.2%.

A study on the degradation of direct pink by the low-frequency ultrasonic irradiation

2010 ◽  
Vol 62 (4) ◽  
pp. 829-836 ◽  
Author(s):  
Huaili Zheng ◽  
Guocheng Zhu ◽  
Qiang He ◽  
Peng Hu ◽  
Shijun Jiao ◽  
...  
Keyword(s):  
Ph Value ◽  
Low Frequency ◽  
Alkaline Condition ◽  
Inorganic Salts ◽  
Ultrasonic Power ◽  
Optimum Conditions ◽  
Initial Ph ◽  
H2o2 Oxidation ◽  
Ultrasonic Degradation ◽  
Degradation Degree

The ultrasonic degradation of direct pink was investigated in this study. Parameters affecting ultrasonic degradation degree such as ultrasonic power, pH, bubbling gas and the presence of inorganic salts, were examined. The results showed that the addition of inorganic salts (NaCl, CuSO4) facilitated the degradation of direct pink while the addition of K2CO3 inhibited it. The degradation degree was enhanced significantly in the presence of saturated gases as listed here in decreasing order of effectiveness: argon > air > oxygen > nitrogen. The degradation degree of direct pink was largely influenced by pH value and boosted by acidic condition. The optimum degree could be achieved when pH value was 3.0 or when the sound power was 150 W. However, the degradability decreased notably in alkaline condition. Also, ultrasound/H2O2 technology was used, and the results showed that ultrasound/H2O2 has a better effect on the degradation than ultrasound alone or with H2O2 oxidation. After 120 minutes, the degradation degree could reach 78.0% under the optimum conditions, when the ultrasonic power was 150 W, 50 μL H2O2, CuSO4 and argon atmosphere being added and the initial pH value of the model dye was 3.0.

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