scholarly journals Efficient Loading of Mano Mn Particles On Calcined Laterite Soil (Lt-nMn) For Higher Removal of As(III) Ions From Groundwater: Adsorption And Eco-Scale Analysis

2021 ◽  
Author(s):  
Roshan Prabhakar ◽  
Somaparna Ghosh ◽  
Ali Malik ◽  
Sukha Ranjan Samadder
Keyword(s):  
Removal Efficiency ◽  
Chemical Reduction ◽  
Base Material ◽  
Oxidation Mechanism ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Order Kinetic ◽  
Laterite Soil ◽  
Nano Coating ◽  
Method Of Production

Abstract Occurrence of arsenic in the groundwater has become a cause for concern in many countries. The presence of As(III) species in the groundwater had been one of the biggest challenges for the water workers especially in the south east Asian countries. Nano based adsorption techniques are gaining attention among researchers for the removal of arsenic ions. However, synthesis of nano-adsorbents is a costly affair. Therefore, the present study utilized the cheap and readily available laterite soil as a base material for nano coating. Nano sized manganese (nMn) particles were synthesized by chemical reduction method and later coated on calcined laterite (Lt-nMn). Coating with 0.1 M nMn provided the best As(III) removal efficiency. The prepared material was characterised for its morphological and surface properties. Phase analysis using XRD (X-ray diffraction) showed the presence of zero valent manganese species, which assisted in adsorption. Adsorption studies were conceded by selecting the different affecting parameters such as contact time, concentration, dose, temperature, and pH. Very high removal in less time regime led to the investigation of the oxidation mechanism. Phosphate and sulphate anions insignificantly reduced the removal efficiency. Langmuir model for the sorption isotherms and pseudo-second order kinetic model for the sorption kinetics symbolized the experimental data. Sustainability studies in terms of eco-scaling and cost analysis were performed for the applied method of production of the nano materials. Adsorber design analysis was also conducted to estimate the required amount of Lt-nMn particles for achieving the desired equilibrium As(III) concentration.

scholarly journals Sorption of the Direct Black 22 dye in alluvial soil

2020 ◽  
Vol 15 (4) ◽  
pp. 1
Author(s):  
Jeisiane Isabella da Silva Alexandre ◽  
Severino Martins dos Santos Neto ◽  
Artur Paiva Coutinho ◽  
Tássia Dos Anjos Tenório de Melo ◽  
Elizabeth Amaral Pastich Gonçalves ◽  
...  
Keyword(s):  
Experimental Data ◽  
Water Conservation ◽  
Groundwater Resources ◽  
Subsurface Layer ◽  
Alluvial Soil ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Second Order ◽  
Order Kinetic ◽  
Direct Black 22

The semiarid region of Pernambuco has a large water deficit, leading the population to explore groundwater resources such as alluvial aquifers. The state of Pernambuco also stands out for having the second-largest textile manufacturing center in Brazil. However, the direct discharge of textile effluents from the region's industries has intensified the negative impacts on water conservation and alluvial soils. This work characterized the sorption of Direct Black 22 dye (DB22) in two layers of alluvial soil in the Capibaribe-PE basin. Batch experiments (kinetics and sorption isotherms) allowed the evaluation of the retention potential and mobility of this compound in this environment. Sorption kinetics were verified for stirring times of 0.25; 0.5; 1; 2; 4; 6; 8; 10; 12; 24; 48 and 72 hours and the experimental data was adjusted to the first- and second-order kinetic models. The isotherm occurred with concentrations of 1; 5; 10; 15; 20; 32.5 and 40 mg.L-1 and experimental data was adjusted to the linear, Freundlich and Langmuir models. The sorption kinetics of DB22 was best described by the second-order model, while the Freundlich and Linear models properly fitted sorption isotherms for Layers 1 and 2. The organic matter contents and the cation-exchange capacity of the soil layers influenced the sorption of the dye. The superficial layer privileges dye retention phenomena, while in the subsurface layer dye mobility phenomena prevail.

scholarly journals Evaluation and mechanism of ammonia nitrogen removal using sediments from a malodorous river

2018 ◽  
Vol 5 (3) ◽  
pp. 172257 ◽  
Author(s):  
Xing Chen ◽  
Xia Jiang ◽  
Wei Huang
Keyword(s):  
Removal Efficiency ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Ammonia Nitrogen ◽  
Main Function ◽  
N Removal ◽  
Maximum Sorption ◽  
Pseudo Second Order ◽  
Unpleasant Smell ◽  
Beijing China

Malodorous rivers are among the major environmental problems of cities in developing countries. In addition to the unpleasant smell, the sediments of such rivers can act as a sink for pollutants. The excessive amount of ammonia nitrogen (NH 3 −N) in rivers is the main factor that causes the malodour. Therefore, a suitable method is necessary for sediment disposition and NH 3 −N removal in malodorous rivers. The sediment in a malodorous river (PS) in Beijing, China was selected and modified via calcination (PS-D), Na + doping (PS-Na) and calcination–Na + doping (PS-DNa). The NH 3 −N removal efficiency using the four sediment materials was evaluated, and results indicated that the NH 3 −N removal efficiency using the modified sediment materials could reach over 60%. PS-DNa achieved the highest NH 3 −N removal efficiency (90.04%). The kinetics study showed that the pseudo-second-order model could effectively describe the sorption kinetics and that the exterior activated site had the main function of P sorption. The results of the sorption isotherms indicated that the maximum sorption capacities of PS-Na, PS-D and PS-DNa were 0.343, 0.831 and 1.113 mg g −1 , respectively, and a high temperature was favourable to sorption. The calculated thermodynamic parameters suggested that sorption was a feasible or spontaneous (Δ G  < 0), entropy-driven (Δ S  > 0), and endothermic (Δ H  > 0) reaction.

scholarly journals Adsorption Studies of Nitrate by Geo-Physical Environment (Laterite Soil) of the Study Area Bidar Urban & its Industrial Area, Karnataka State, India

2013 ◽  
Vol 11 ◽  
pp. 66-76
Author(s):  
Shivasharanappa ◽  
Padaki Srinivas ◽  
Srinivas Kushtagi
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Nitrate Removal ◽  
Industrial Area ◽  
Sorption Kinetics ◽  
Batch Adsorption ◽  
Laterite Soil ◽  
Optimum Dosage ◽  
Karnataka State ◽  
Optimum Ph

In the present work, adsorption of Nitrate on Laterite soil has been studied using batch adsorption techniques. Main objectives of this study is to study the physical properties of Laterite soil, detection of Nitrate removal by adsorbent Laterite soil as a function of contact time, adsorbent dosage, pH, to study sorption kinetics, and to study isothermal pattern. The results of this study showed that the Optimum contact time, Optimum dosage and Optimum pH for adsorption of Nitrate on Laterite soil reached to equilibrium after 130 minutes, with removal efficiency of 68 %, 1400 mg as optimum dosage and at optimum pH of 6. The rate of adsorption of Nitrate obeys first order rate equation. The obtained results of the batch experiments are best fitted to Langmuir and Freundlich adsorption isotherms. From the experimental analysis it is concluded that Laterite soil shows good removal efficiency and hence can be used as adsorbent.

Synthesis of Functionalized Magnetite Titanium Dioxide Nanocomposite for Removal of Acid Fuchsine Dye

2018 ◽  
Vol 21 (8) ◽  
pp. 583-593 ◽  
Author(s):  
Sara Rahnama ◽  
Shahab Shariati ◽  
Faten Divsar
Keyword(s):  
Titanium Dioxide ◽  
Removal Efficiency ◽  
Magnetic Core ◽  
Fractional Factorial ◽  
Order Kinetic ◽  
Sorption Data ◽  
Salt Addition ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

Objective: In this research, a novel magnetite titanium dioxide nanocomposite functionalized by amine groups (Fe3O4@SiO2@TiO2-NH2) was synthesized and its ability for efficient removal of Acid Fuchsine as an anionic dye from aqueous solutions was investigated. Method: The core-shell structure of Fe3O4@SiO2@TiO2 was prepared using Fe3O4 as magnetic core, tetra ethyl orthosilicate as silica and tetra butyl titanate as titanium source for shell. The synthesized nanocomposites (particle size lower than 44 nm) were characterized by FT-IR, XRD, DRS, SEM and TGA instruments. The various experimental parameters affecting dye removal efficiency were investigated and optimized using Taguchi fractional factorial design. Results: The synthesized adsorbent showed the highest removal efficiency of Acid Fuchsine (99 %) at pH= 3.5, without salt addition and during stirring at contact times less than 10 minutes. The study of kinetic models at two concentration levels showed the fast dye sorption on the surface of proposed nanocomposites with pseudo second order kinetic model (R2=1). Also, the fitting of Acid Fuchsine sorption data to Freundlich, Langmuir and Temkin isotherms suggested that Freundlich model gave a better fitting than other models (R2=0.9936, n=2). Conclusion: Good chemical stability, excellent magnetic properties, very fast adsorption kinetics and high removal efficiency make the synthesized nanocomposite as a proper recoverable sorbent for removal of Acid Fuchsine dye from wastewaters.

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

scholarly journals Removal of hexavalent chromium from wastewater by Cu/Fe bimetallic nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jien Ye ◽  
Yi Wang ◽  
Qiao Xu ◽  
Hanxin Wu ◽  
Jianhao Tong ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Chemical Reduction ◽  
Particle Surface ◽  
Zerovalent Iron ◽  
Order Model ◽  
X Ray ◽  
Nanoscale Zerovalent Iron

AbstractPassivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. In this study, Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. Synthesized bimetallic nanoparticles were characterized by transmission electron microscopy, Brunauer–Emmet–Teller isotherm, and X-ray diffraction. The results showed that Cu loading can significantly enhance the removal efficiency of Cr(VI) by 29.3% to 84.0%, and the optimal Cu loading rate was 3% (wt%). The removal efficiency decreased with increasing initial pH and Cr(VI) concentration. The removal of Cr(VI) was better fitted by pseudo-second-order model than pseudo-first-order model. Thermodynamic analysis revealed that the Cr(VI) removal was spontaneous and endothermic, and the increase of reaction temperature facilitated the process. X-ray photoelectron spectroscopy (XPS) analysis indicated that Cr(VI) was completely reduced to Cr(III) and precipitated on the particle surface as hydroxylated Cr(OH)3 and CrxFe1−x(OH)3 coprecipitation. Our work could be beneficial for the application of iron-based nanomaterials in remediation of wastewater.

scholarly journals Removal Efficiency of Nitrite and Sulfide Pollutants by Electrochemical Process by Using Ti/RuIrO2 Anode

2018 ◽  
Vol 18 (2) ◽  
pp. 286 ◽  
Author(s):  
Aris Mukimin ◽  
Agus Purwanto
Keyword(s):  
Removal Efficiency ◽  
Hydraulic Retention Time ◽  
Oxidation Mechanism ◽  
Electrochemical Process ◽  
Anode Surface ◽  
Electrochemical Technology ◽  
Nitrite Removal ◽  
Biological Methods ◽  
Operation Cost ◽  
Easy Operation

In general, wastewater treatment by physical, chemical and biological methods are only focused on TSS, BOD and COD removals that the effluent still contains anion pollutant as NO2- and S2-. Electrochemical technology is a proper method for those pollutants treatment due to its fast process, easy operation and minimum amount of sludge. Electrocatalytic reactor with 8 L capacity using Ti/RuIrO2 cylinder as anode and Fe plate as cathode was arranged and applied to treat anion pollutants. Hydraulic retention time (30, 60, 90 and 120 min), salt concentration (250, 500 and 750 mg/L) and voltage (4, 5, and 6 V) were chosen as operation variables and NO2- and S2- concentrations as parameter indicators. Nitrite removal efficiency reached 75 and 99.7% after 60 and 120 min of electrolysis, respectively, while sulfide could obtain higher efficiency, i.e., 97 and 99.9% after 60 and 90 min, respectively, at operation variables of potential of 5 V and salt of 500 mg/L. Removal process is dominated by indirect oxidation mechanism by HClO/ClO- oxidators generated at anode surface as intermediate products. The lifespan of electrode and electric consumption are two main factors of operation cost. Electric consumed was 0.452 kWh per 1 g nitrite removed.

scholarly journals USING METAL WASTE SLAGS AS THE HETEROGENEOUS CATALYSTS OF OZONE FOR TREATMENT OF PULP WASTEWATER

2020 ◽  
Vol 58 (3A) ◽  
pp. 1
Author(s):  
Hu Tap Van
Keyword(s):  
Organic Compounds ◽  
Removal Efficiency ◽  
Heterogeneous Catalysts ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Color Removal ◽  
Order Kinetic ◽  
First Order ◽  
Iron Slag ◽  
Ozonation Process

Catalytic ozonation is one of the promising treatment methods for removal of persistent organic compounds from water and wastewater. In this study, some metal slags such as: iron slag, lead slag, zinc slag, cadmium slag and copper slag originated from solid waste of Thai Nguyen Non-ferrous Metals Limited Company, Vietnam were used as heterogeneous catalysts for ozonation process to remove organic compounds from pulp wastewater. The effects of the initial pH (pHi) of pulp wastewater and the metal slag dosage on efficiency of decolorization and mineralization of pulp wastewater, in term of COD were investigated. The results indicated that iron slag was the most suitable catalyst for treatment of pulp wastewater by ozonation process with the highest removal efficiency of COD, namely, after 120 min of ozonation (with flowrate of O3 of 3.038 g/h) of the pulp wastewater (initial COD 1809 mg/L), COD removal efficiency, respectively, reached 91,16%; 84%; 83,83 %; 83,91%; 83,41% and 83,14% in the presence of iron, copper, zinc, lead, cadmium slag and ozone alone. Simultaneously, the color was almost completely removed (95.55 – 98.79%) by ozonation processes with using all before-mentioned metal slags as heterogeneous catalysts and ozone alone. Maximum COD and color removal efficiency obtained at pH 7 for ozonation alone and its combinations with iron slag. Moreover, an increase in the iron slag dosage from 0.125 g/L to 2.0 g/L for O3/iron slag could enhance COD and color removal of pulp wastewater. The K values (apparent first-order rate constant values) showed that the COD removal rate followed the pseudo-first-order kinetic model. This study also indicated that the main constituent FeO presence in iron slag reaction with O3 in heterogeneous catalytic ozonation system enhances removal efficiency of color and COD of pulp wastewater.

scholarly journals A rapid and efficient removal approach for degradation of metformin in pharmaceutical wastewater using electro-Fenton process; optimization by response surface methodology

2019 ◽  
Vol 80 (4) ◽  
pp. 685-694 ◽  
Author(s):  
Maryam Dolatabadi ◽  
Saeid Ahmadzadeh
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Degradation Mechanism ◽  
Pharmaceutical Products ◽  
Oh Radicals ◽  
Order Kinetic ◽  
Pharmaceutical Wastewater ◽  
Efficient Removal ◽  
Solution Ph

Abstract Presence of emerging contaminants such as pharmaceutical products in aquatic environments has received high concern due to their undesirable effect on wildlife and human health. Current work deals with developing a treatment model based on the electro- Fenton (EF) process for efficient removal of metformin (MET) from an aqueous medium. The obtained experimental results revealed that over the reaction time of 10 min and solution pH of 3, the maximum removal efficiency of 98.57% is achieved where the value of MET initial concentration, current density, and H2O2 dosage is set at 10 mg.L−1, 6 mA.cm−2, and 250 μL.L−1, respectively, which is in satisfactory agreement with the predicted removal efficiency of 98.6% with the desirability of 0.99. The presence of radical scavengers throughout the mineralization of MET under the EF process revealed that the generation of •OH radicals, as the main oxidative species, controlled the degradation mechanism. The obtained kinetics data best fitted to the first order kinetic model with the rate constant of 0.4224 min−1 (R2 = 0.9940). The developed treatment process under response surface methodology (RSM) was employed for modeling the obtained experimental data and successfully applied for efficient removal of the MET contaminant from pharmaceutical wastewater as an adequate and cost-effective approach.

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