scholarly journals Oxidation of Sulfamethoxazole by Rice Husk Biochar-Activated Persulfate

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 850
Author(s):  
Efstathios Avramiotis ◽  
Zacharias Frontistis ◽  
Ioannis D. Manariotis ◽  
John Vakros ◽  
Dionissios Mantzavinos
Keyword(s):  
Rice Husk ◽  
Calcium Nitrate ◽  
Physicochemical Characterization ◽  
Complete Removal ◽  
Significant Inhibition ◽  
Order Kinetic ◽  
Oxygen Control ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Rice Husk Biochar

In the present study, biochars from rice husk were synthesized via pyrolysis at 400, 550, 700 and 850 °C for 1 h under a limited O2 atmosphere, characterized with a various techniques of and used as catalysts to activate persulfate and to degrade sulfamethoxazole (SMX). After physicochemical characterization of biochars. SMX degradation tests were performed using different water matrices, persulfate biochar and SMX concentrations and different initial pH solutions. Also, spiked solutions with bicarbonate, chloride, calcium nitrate, humic acid or alcohols were tested. It was found that catalytic reactivity rises with the pyrolysis temperature. Biochar is crucial for the oxidation of SMX and it can be described with a pseudo first–order kinetic model. Real matrices hinder the oxidation process, in waste water the SMX removal is 41% in 90 min, comparable with the inhibition obtained with spiked with bicarbonates solution (52% removal within 90 min) while complete removal can be achieved in ultrapure water matrices. The presence of alcohol slightly inhibits degradation contrary to the addition of sodium azide which causes significant inhibition, this is an evidence that degradation either under electron transfer/singlet oxygen control or dominated by surface-bound radicals.

Preparation of Graphene Oxide Modified Rice Husk for Cr(VI) Removal

2019 ◽  
Vol 19 (11) ◽  
pp. 7035-7043 ◽  
Author(s):  
Tong Ouyang ◽  
Jidan Tang ◽  
Fang Liu ◽  
Chang-Tang Chang
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Alkaline Conditions ◽  
Rice Husk Biochar

The objective of this paper is to study the removal of Cr(VI) in aqueous solution by using a new graphene oxide-coated rice husk biochar composite (GO-RHB). GO-RHB is a synthetic material having a porous structure with lots of oxygen-containing functional groups and a large surface area that provide effective adsorption sites. Experiments showed that GO-RHB had higher adsorption capacity under acidic than under alkaline conditions. At pH of 2, GO-RHB has the maximum adsorption capacity(48.8 mg g−1). Equilibrium data obtained by fitting with the Langmuir and Freundlich models indicate that the reaction process was monolayer adsorption. The adsorption of Cr(VI) followed the pseudo-second-order kinetic model that illustrates chemical adsorption. Intraparticlediffusion studies further revealed that film diffusion was taking place. Moreover, the results of thermodynamics showed that the adsorption process was endothermic and spontaneous in nature. The removal mechanism of Cr(VI) was also explained in detail. The prepared adsorbent is highly efficient and might be useful than many other conventional adsorbent used for the removal of Cr(VI) from wastewater.

scholarly journals Removal of Estrogen Hormones (17β-Estradiol and Estrone) from Aqueous Solutions Using Rice Husk Silica

2019 ◽  
Vol 33 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Mohammad Hasan Zarghi ◽  
Aliakbar Roudbari ◽  
Sahand Jorfi ◽  
Neamat Jaafarzadeh
Keyword(s):  
Aqueous Solutions ◽  
Rice Husk ◽  
Acid Leaching ◽  
Acid Mixture ◽  
Order Kinetic ◽  
Mazandaran Province ◽  
Rice Husk Silica ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
17Β Estradiol

The aim of this study was to investigate the removal of estrogen hormones (17β-estradiol and estrone) from aqueous solutions using rice husk extracted silica. Rice husk was collected from rice factories in Mazandaran province (Iran) and the adsorbent was prepared in a furnace at 800 °C for 4 h, after acid leaching with hydrochloric and sulfuric acid mixture. Optimal operating parameters for estrogen removal were determined, including initial pH values (4–9), adsorbent dosages (0.5, 1, 1.5, and 2 g L–1), contact times (30, 60, 90, and 120 min), and initial concentrations of 17β-estradiol and estrone (10, 40, 70 and 100 ng L–1); one-factor-at-a-time method was used. The method of electrochemiluminescence was used to measure the concentration of hormones. Kinetic adsorption models and adsorption isotherms were also studied. The maximum removal efficiency (%) of 17β-estradiol (E2) and estrone (E1) hormones of 95.5 and 93.1 %, respectively, was obtained at optimal conditions of pH 4, 1.5 g L–1 of adsorbent dosage, 60 min of contact time and 10 ng L–1 initial concentrations of E2 and E1. Pseudo first-order kinetic model and Langmuir adsorption isotherm had the best fit with experimental data for both estrogen hormones, following nonlinear regression procedure. Rice husk silica could be considered as effective and accessible adsorbent for removal of estrogenic hormones.

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

scholarly journals Factors influencing the adsorption and photocatalysis of direct red 80 in the presence of a TiO2: Equilibrium and kinetics modeling

2021 ◽  
pp. 174751982198996
Author(s):  
Moussa Abbas
Keyword(s):  
Elimination Rate ◽  
Threshold Value ◽  
Heterogeneous Photocatalysis ◽  
Order Kinetic ◽  
Batch Mode ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Equilibrium And Kinetics ◽  
Order Kinetic Model ◽  
Charge Point

Among the different photocatalysts, TiO2 ( Eg = 3.1 eV, zero charge point (pHpzc = 6.3), and surface = 55 m2/g) is currently the most efficient and the most studied semiconductor due to its strong photocatalytic activity, non-toxicity, and chemical stability. The elimination of DR-80 on TiO2 is studied by adsorption in batch mode and by application of heterogeneous photocatalysis onto TiO2 under UV irradiation. The effects of contact time (0–60 min), initial pH (3–11), dose of the adsorbent (0.5–3 g L−1), and DR-80 concentration (40–60 mg L−1) on the adsorption of DR-80 by TiO2 are studied for optimization of these parameters. The kinetic parameters, rate constants, and equilibrium adsorption capacities are calculated and discussed for each applied theoretical model. The adsorption of DR-80 is well described by the pseudo-first-order kinetic model. The fitting of the adsorption isotherms shows that the models of Langmuir and Temkin offering a better fit and an adsorption 64.102 mg/g at 25 °C of DR-80 are eliminated. The results showed that the photocatalytic efficiency strongly depends on the pH while the initial rate of photodegradation is proportional to the catalyst dose, and becomes almost constant above a threshold value. It was found that the photodegradation is favored at low DR-80 concentrations in accordance with the Langmuir–Hinshelwood model with the constants Kad = 6.5274 L/mg and KL–H = 0.17818 mg L−1 min. However, the adsorption is improved for high DR-80 concentrations. It is found that the degradation depends on both the temperature and the pH with a high elimination rate at high temperature. The photocatalyst TiO2 has a better activity for the degradation of DR-80, compared to some commercial catalysts that have been described in the literature.

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

scholarly journals Optimization of cadmium(II) adsorption onto modified and unmodified lignocellulosics (rice husk and egussi peeling)

2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Batch Technique ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbed Quantity ◽  
Minimal Mass ◽  
Modified Adsorbents

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>

Adsorption of Chromium (VI) from Aqueous Solution by Agricultural Waste Derived Activated Carbon

2013 ◽  
Vol 726-731 ◽  
pp. 2100-2106 ◽  
Author(s):  
Hua Zhang ◽  
Xue Hong Zhang ◽  
Yi Nian Zhu ◽  
Shou Rui Yuan
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Agricultural Waste ◽  
Order Kinetic ◽  
Chromium Vi ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Grapefruit Peel ◽  
Pseudo Second Order ◽  
C 30

Activated carbon prepared from grapefruit peel, an agricultural solid waste by-product, has been used for the adsorption of Cr(VI) from aqueous solution. The effects of adsorbent dosage, pH and temperature on adsorption of Cr(VI) were investigated. The maximum adsorption yield was obtained at the initial pH of 3. The dynamical data fit very well with the pseudo-second-order kinetic model and the calculated adsorption capacities (23.98, 24.33 and 24.81 mg/g) were in good agreement with experiment results at 20°C, 30°C and 40 °C for the 100 mg/L Cr(VI) solution. The Freundlich model (R2 values were 0.9198-0.9871) fitted adsorption data better than the Langmuir model. The calculated parameters confirmed the favorable adsorption of Cr(VI) on the activated carbon prepared from grapefruit peel.

Biosorption of hexavalent chromium from aqueous solution by polyethyleneimine-modified ultrasonic-assisted acid hydrochar from Sargassum horneri

2020 ◽  
Vol 81 (6) ◽  
pp. 1114-1129 ◽  
Author(s):  
Jun Wang ◽  
Qinglong Xie ◽  
Ao Li ◽  
Xuejun Liu ◽  
Fengwen Yu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Batch Adsorption ◽  
Crosslinking Reaction ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Ultrasonic Assisted ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract In this study, an efficient route to synthesizing polyethyleneimine-modified ultrasonic-assisted acid hydrochar (PEI-USAH) is developed and reported. Ultrasonic irradiation technique was used as surface modification method to shorten the crosslinking reaction for hydrochar and polyethyleneimine (PEI). The PEI-USAH showed an excellent adsorption capacity for Cr(VI) from aqueous solution. The physicochemical properties of this PEI-modified adsorbent were comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis and CNHS analysis. The effects of contact time, initial pH, and biosorbent dose on adsorption capacities were investigated. The batch adsorption experiments showed that PEI-USAH possessed the maximum adsorption capacities of 94.38 mg/g and 330.84 mg/g for initial Cr(VI) concentration of 100 mg/L and 500 mg/L, respectively. Furthermore, this adsorption process could be fitted to Langmuir adsorption and described by the pseudo second order kinetic model. Based on the above findings, PEI-USAH could be used as a potential adsorbent for removal of Cr(VI) from wastewater.

Adsorption kinetics and isotherm of vanadium with melamine

2017 ◽  
Vol 75 (10) ◽  
pp. 2316-2321 ◽  
Author(s):  
Hao Peng ◽  
Zuohua Liu ◽  
Changyuan Tao
Keyword(s):  
Adsorption Kinetics ◽  
Impact Factors ◽  
Order Kinetic ◽  
Freundlich Model ◽  
Initial Ph ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorption Kinetics And Isotherm ◽  
Langmuir And Freundlich Models

Melamine, possessing three free amino groups and three aromatic nitrogen atoms in its molecule, has great potential as an adsorbent for metal ions. We investigated three impact factors of the adsorption process: the initial pH of the vanadium solution, contact time and reaction temperature. The adsorption kinetics could be accurately described by the pseudo-second-order kinetic model. Langmuir and Freundlich models fitted well with the experimental equilibrium data, and the maximal adsorption capacity was found to be 1,428.57 mg vanadium/g melamine, and the Freundlich model showed the adsorption is privilege type.

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