scholarly journals Synthesis of Nd-doped ZSM-5 and its application to treating slightly polluted water

2017 ◽  
Vol 8 (1) ◽  
pp. 86-93
Author(s):  
Mang Lu ◽  
Lin He ◽  
Yue Cheng
Keyword(s):  
Contact Time ◽  
Oxygen Demand ◽  
Raw Material ◽  
Molar Ratio ◽  
Polluted Water ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Factors Influencing ◽  
Orthogonal Experiments ◽  
Removal Efficiencies

Abstract In this study, ZSM-5 zeolite was synthesized using diatomaceous mud as the raw material, and then doped with different amounts of Nd2O3. The orthogonal experiments were performed to investigate the influence of Nd:Si molar ratio, zeolite dosage, contact time, solution pH and temperature on the removal of humic acid (HA). The removal of HA was comprehensively evaluated by chemical oxygen demand (COD), UV254 and UV410 of the solution. The results demonstrate that solution pH and zeolite dosage are the two most important factors influencing HA adsorption. The optimum experimental conditions were determined to be: 35 °C, Nd:Si molar ratio of 1:100, 2.0 g/L zeolite, pH 4 and 50 min contact time. Under these conditions, the removal efficiencies of UV254, UV410 and COD are 82.70%, 76.00% and 82.10%, respectively, corresponding to a comprehensive removal of 81.02%.

scholarly journals Red Mud-Based Polyaluminum Ferric Chloride Flocculant: Preparation, Characterization and Flocculation Performance

2021 ◽  
Author(s):  
Yong Cheng ◽  
Longjun Xu ◽  
Chenglun Liu ◽  
Zao Jiang ◽  
Qiyuan Zhang ◽  
...  
Keyword(s):  
Red Mud ◽  
High Efficiency ◽  
Low Cost ◽  
Oxygen Demand ◽  
Industrial Applications ◽  
Iron Chloride ◽  
Raw Material ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
Solution Ph

Abstract In this work, red mud was used as raw material to extract Al and Fe with hydrochloric acid. The high-efficiency polyaluminum iron chloride (PAFC) flocculant was prepared via adjusting the pH of the leaching solution, the molar ratio of aluminum and iron, and the polymerization temperature. The effect of synthesis and flocculation conditions on the flocculation performance of aged landfill leachate was investigated. The results confirmed that the PAFC prepared at the polymerization pH of 2.5, the Al/Fe molar ratio of 8, and the polymerization temperature of 70 °C had the optimum flocculation effect. The flocculation consequences of PAFC and commercial polyaluminum iron chloride flocculant (CPAFC) under different flocculation conditions were compared. The chemical oxygen demand (COD), UV254, chroma and settlement height of PAFC at flocculant concentration of 60 g/L and solution pH of 6 were 72.2%, 79.2%, 82.9% and 9.5 cm (within 90 min), respectively. PAFC has excellent flocculation performance and can be used as a simple, potentially low-cost wastewater treatment agent in industrial applications.

Influence of Operating Conditions on the Persulfate Oxidation of Textile Waste Water at Ambient Temperature

2015 ◽  
Vol 802 ◽  
pp. 454-459 ◽  
Author(s):  
Fagbenro Oluwakemi Kehinde ◽  
Hamidi Abdul Aziz
Keyword(s):  
Contact Time ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Textile Wastewater ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Solution Ph ◽  
Persulfate Oxidation ◽  
Ambient Temperatures ◽  
Textile Waste Water

At the ambient temperatures, the influence of operating conditions on persulfate (S2O8) oxidation of real textile wastewater was investigated for the removal of color, suspended solids (SS) and chemical oxygen demand (COD). The effects of oxidant dosage, initial solution pH and contact time were studied in a series of batch experiments using persulfate (PS) oxidant as sodium persulfate. Oxidant dose was defined by an oxidant/contaminant (PS/COD) molar ratio, varied from 1/1-10/1. Although parameter removals increased with the oxidant dose, especially for color and SS, a PS/COD molar ratio of 4/1 (6720mg/L) was adopted in a bid to use fewer chemicals. The pH was varied from 2-11, with pH of between 2 and 3 being the optimum. At 360minutes contact time, the removals of color, SS and COD were 84%; 71% and 32% respectively. Although relatively effective, especially for color removal, results show that the reactions might have been inhibited at ambient temperatures as shown by the particularly low removal of COD.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

A Novel Method on Simultaneous Removal of SO2, NO and Hg0 from Simulated Flue Gas

2013 ◽  
Vol 316-317 ◽  
pp. 214-218 ◽  
Author(s):  
Yi Zhao ◽  
Fang Ming Xue ◽  
Yuan Shao
Keyword(s):  
Reaction Temperature ◽  
Flue Gas ◽  
Solution Concentration ◽  
Simultaneous Removal ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Wet Process ◽  
Temperature Solution ◽  
Novel Method ◽  
Removal Efficiencies

A novel wet process has been developed to simultaneously remove NO, SO2 and Hg0 from flue gas. According to the conditions of the bubbling reactor, diperiodatocuprate (Ⅲ) coordination ion solution was prepared with CuSO4•5H2O, KIO4, K2S2O8, and KOH, and the effects of the various influencing factors, such as diperiodatocuprate (Ⅲ) coordination ion solution concentration, reaction temperature, solution pH on removal efficiencies were investigated. The removal efficiencies of 98% for SO2, 90% for Hg0 and 56.8% for NO were obtained, respectively, under the optimal experimental conditions, in which diperiodatocuprate (Ⅲ) coordination ion solution concentration was 6 mmol /L, the reaction temperature was 323 K, and the solution pH was 9.0. That [Cu(OH)2(H3IO6)]- was the main existing form of the absorbent at the optimal experimental conditions was confirmed by calculating the concentration ratios of IO4- and its dissociation products / [IO4-]ex under different pH, and thereby simultaneous removal mechanism for SO2, NO and Hg0 was proposed.

scholarly journals THE APPLICATION OF WHEAT BRAN FOR THE REMOVAL OF COPPER IONS FROM POLLUTED WATER

2020 ◽  
Author(s):  
Gideon Masedi Nii Ayi Lomoko ◽  
Dainius Paliulis
Keyword(s):  
Metal Concentration ◽  
Wheat Bran ◽  
Contact Time ◽  
Room Temperature ◽  
Copper Ions ◽  
Polluted Water ◽  
Adsorption Efficiency ◽  
Toxic Heavy Metals ◽  
Solution Ph ◽  
Adsorbent Dose

The purpose of the study underlying the present paper was to determine the adsorption of copper ions which happens to be one of the most important toxic heavy metals in the environment; for that purpose a test was carried out under laboratory conditions using wheat bran as adsorbent. The object of the test was to examine the effect of solution pH, contact time, adsorbent dose and initial copper ions concentration (2 mg/L to 20 mg/L) on adsorption yield and uptake. Three masses of wheat bran (0.5 g, 1.0 g and 2.0 g) were used for this experiment. 1.0 g of wheat bran gave a maximum adsorption efficiency at pH 5.0. At this pH, the adsorption efficiency for initial copper ions concentration of 5 mg/L was found to be 65.8% at room temperature for a contact time of 60 min. The adsorption of copper ions slowly reached equilibrium at 30 mins. With an adsorbent dose of 0.5 g of wheat bran, a maximum uptake of 0.277 mg/g of copper ions was recorded. With increasing mass of adsorbent dose from 0.5 g to 2.0 g. the adsorption uptake of copper ions decreased from 0.273 mg/g to 0.087 mg/g The highest removal efficiency of copper ions was found to be at a metal concentration of 5 mg/L. With the metal concentration increasing the adsorption of copper ions by 0.5 g of wheat bran decreased from 52.0% to 39.9%.

scholarly journals Synthesis and Characterization of a Chemically-Activated Novel Mesoporous Silica for Cobalt Decontamination from Polluted Water

2019 ◽  
Vol 14 (2) ◽  
pp. 276-289 ◽  
Author(s):  
Sina Matavos-Aramyan ◽  
Sadaf Soukhakian
Keyword(s):  
Mesoporous Silica ◽  
Contact Time ◽  
Aqueous Media ◽  
Co2 Concentration ◽  
Polluted Water ◽  
Co2 Removal ◽  
High Porosity ◽  
Order Kinetic ◽  
Solution Ph ◽  
Adsorbent Dose

Mesoporous silica was synthesized by a chemical process and its efficiency was investigated for removal of cobalt (Co2+) ions from contaminated water in a laboratory scale. The characteristics of synthesized mesoporous were analyzed by SEM/TGA. Optimal conditions were determined for important parameters such as solution pH, the absorbent dose, the initial Co2+ concentration, and contact time by a single-variable method through the batch experiments. The SEM results confirmed the synthesized silica had high porosity with a honeycomb-like structure. The results showed that with an increasing adsorbent dose and contact time to the optimum, the efficiency of Co2+ adsorption increased. However, with increasing concentration of Co2+, the removal efficiency decreased. At optimal contact time (8 h), 85 % of Co2+ was removed. The maximum adsorption efficiency at pH =7, initial Co2+ concentration of 5 ppm, and at the adsorbent dose 0.3 g/50 ml, was 89%. The study of adsorption isotherm and kinetic models showed that the adsorption process followed the Freundlich isotherm (R2 = 0.9359) and the second-order kinetic model (R2=0.999). Therefore, the synthesized mesoporous silica presented a chemical adsorption mechanism for Co2+ removal from aqueous media and can be utilized in wastewater treatment containing divalent heavy metals such as Co2+.

scholarly journals Removal of COD, NH4-N, and perfluorinated compounds from wastewater treatment plant effluent using ZnO-coated activated carbon

2020 ◽  
Author(s):  
Jiawei Tang ◽  
Yu Liu ◽  
Peidong Su ◽  
Jingwei Quan ◽  
Yufeng Hu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Carbon ◽  
Wastewater Treatment Plant ◽  
Contact Time ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Perfluorinated Compounds ◽  
Optimal Dosage ◽  
Membrane Diffusion ◽  
Removal Efficiencies

Abstract This study investigated the removal of chemical oxygen demand (COD), NH4-N, and perfluorinated compounds (PFCs) in the effluent from a wastewater treatment plant (WWTP) using ZnO coated activated carbon (ZnO/AC). Results suggested that the optimal dosage of the ZnO/AC was 0.8 g/L within 240 min of contact time, at which the maximum removal efficiency of COD was approximately 86.8%, while the removal efficiencies of PFOA and PFOS reached 86.5% and 82.1%. In comparison, the removal efficiencies of NH4-N, PFBA, and PFBS were lower, at approximately 47.9%, 44.0%, and 55.4%, respectively. In addition, COD was preferentially adsorbed before PFCs and NH4-N, when the contact time ranged from 0 to 180 min, and the order of PFCs removal showed a positive correlation with C-F chain length. The kinetic study revealed that the removal of COD, NH4-N, and PFCs could be better depicted and predicted by the Lagergren quasi-second order dynamic model with high correlation coefficients, which involved liquid membrane diffusion, intraparticle diffusion, and photocatalytic reactions. The saturated ZnO/AC was finally regenerated using ultrasound for 3 h and retained excellent performance, which proved it could be considered as an effective and alternative technology.

Two-Step Preparation of Bio-Diesel from the Used Bleaching Clay

2012 ◽  
Vol 209-211 ◽  
pp. 1774-1777
Author(s):  
Su Xi Wu ◽  
Shuai Hang Yan ◽  
Hui Cai
Keyword(s):  
Reaction Time ◽  
Maximum Yield ◽  
Acid Value ◽  
Raw Material ◽  
Bleaching Clay ◽  
Molar Ratio ◽  
Alkaline Catalyst ◽  
Orthogonal Experiments ◽  
Optimal Reaction Condition ◽  
Optimal Reaction

with the shortage of the raw material oil for producing bio-diesel in China, the oil, recovered from the used bleaching clay which often be discarded by vegetable oil factory, was used to prepare bio-diesel in this trial. Two-step catalyzed process was adopted to produce biodiesel from the oil. The effect of methanol-to-oil molar ratio, alkaline catalyst quantity, reaction temperature and reaction time on the preesterification and transesterification reaction was investigated through orthogonal experiments. Thus the optimal reaction condition came out. Firstly, the optimal pre-esterification condition, under which the end acid value of the product was minimum (i.e. 1.88 mgKOH/g),was to react for 40 h at 60°C,with a methanol-to-oil molar ratio of 12:1, and by adding alkali catalyst 4% based on the oil weight. Secondly，the optimal transesterification condition, under which the maximum yield of bio-diesel can reach up to 98.2%, was to react for 2.5 h at 60°C,with the methanol-to-oil molar ratio of 7:1, and by adding catalyst 1.25% based on the oil weight.

Removal of Copper (II) Ions from Polluted Water Using Modified Wheat Bran

2021 ◽  
Vol 25 (1) ◽  
pp. 853-864
Author(s):  
Gideon Masedi Nii Ayi Lomoko ◽  
Dainius Paliulis ◽  
Karlis Valters
Keyword(s):  
Wheat Bran ◽  
Contact Time ◽  
Metal Ion ◽  
Model Fitting ◽  
Ion Concentration ◽  
Polluted Water ◽  
Maximum Efficiency ◽  
Solution Ph ◽  
Living Organisms

Abstract The discharge of wastewater containing heavy metals into waterbodies is a major environmental issue that can influence the quality of the water supply; therefore, it is important to remove the pollutants dangerous to living organisms. The adsorption of copper (II) ions on modified wheat bran was investigated with respect to initial solution pH (2.0-7.0), contact time (5–120 min), adsorbent mass (0.5 g and 1.0 g), and initial metal ion concentration (2.0–20 mg/L). The optimum adsorption conditions were found to be at pH 5.0 and a contact time of 60 min with an adsorbent mass of 1.0 g where the maximum efficiency was recorded as 84.5 %. The adsorption uptake (in mg/g) of copper (II) ions slowly reached equilibrium in around 30 min and this amount was 0.30 mg/g using an adsorbent mass of 0.5 g. The adsorption uptake of copper (II) ions decreased with increasing mass of adsorbent and the adsorption efficiency (in %) increased with increasing mass of adsorbent. The experimental results were described using the Langmuir and Freundlich models, with the Langmuir model fitting better than the Freundlich model. The maximum modelled adsorption capacity was 4.24 mg/g and the modelled specific surface area of modified wheat bran was 6.36 m2. It was observed that the adsorption of copper (II) ions on modified wheat bran is efficient and suitable, therefore modified wheat bran is a relatively good adsorbent for the removal of copper (II) ions from polluted water compared to other agricultural adsorbents.

scholarly journals Cleaner Production Assessment of Fast Bordeaux GP Base

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Mausumi Mukhopadhyay ◽  
Rashmita D. Patel
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Chemical Oxygen Demand ◽  
Pilot Plant ◽  
Oxygen Demand ◽  
Feasibility Studies ◽  
Cleaner Production ◽  
Raw Material ◽  
Molar Ratio ◽  
High Chemical Oxygen Demand

The pilot plant study of cleaner production (CP) process of a dyes intermediate, Fast Bordeaux GP Base (2-nitro-p-anisidine), is presented in this work. The existing production process with acetic anhydride as raw material generates highly polluting (high chemical oxygen demand), huge-volume effluent, and thus the treatment is expensive. In the proposed process, raw material acetic anhydride in acetylation step is replaced with acetic acid. The reaction conditions like reaction time (3 h), temperature (120∘C) and molar ratio of p-anisidine and acetic acid (1 : 3.58) are optimized in the laboratory scale and implemented in pilot plant. The extent of conversion has been monitored by nitrite value test, and purity of product mixture is measured with thin-layer chromatography (TLC). The acidic wastewater quantity is dramatically reduced by incorporating recycling in washing scheme, and thus water consumption is reduced. Reduction in wastewater generation and reduction/elimination of treatment cost is also observed. Chemical oxygen demand (COD) of the effluent stream is reduced by the recovery of by-products sodium acetate and spent acid. The technoeconomical feasibility studies show that the proposed CP options are highly economical and environmental friendly.

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