Controlled Zn1−xNixO nanostructures for an excellent humidity sensor and a plausible sensing mechanism

2018 ◽  
Vol 42 (11) ◽  
pp. 8445-8457 ◽  
Author(s):  
Alfa Sharma ◽  
Yogendra Kumar ◽  
Kushal Mazumder ◽  
Amit Kumar Rana ◽  
Parasharam M. Shirage
Keyword(s):  
Adsorption Isotherm ◽  
Humidity Sensor ◽  
Isotherm Model ◽  
Humidity Sensing ◽  
Sensing Mechanism ◽  
Freundlich Adsorption Isotherm

A Freundlich adsorption isotherm model confirms a plausible humidity sensing mechanism when using wet chemically prepared Zn1−xNixO nanostructures.

scholarly journals Paper-Based ZnS:Cu Alternating Current Electroluminescent Devices for Current Humidity Sensors with High–Linearity and Flexibility

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4607 ◽  
Author(s):  
Yaqin He ◽  
Mengyao Zhang ◽  
Nan Zhang ◽  
Danrong Zhu ◽  
Chun Huang ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Silver Nanowires ◽  
Alternating Current ◽  
Sensor Technology ◽  
Sensing Element ◽  
Humidity Sensors ◽  
Phosphor Layer ◽  
Humidity Sensing ◽  
Electroluminescent Devices ◽  
Sensing Mechanism

Humidity sensors are indispensable for various electronic systems and instrumentations. To develop a new humidity sensing mechanism is the key for the next generation of sensor technology. In this work, a novel flexible paper-based current humidity sensor is proposed. The developed alternating current electroluminescent devices (ACEL) consist of the electroless plating Ni on filter paper and silver nanowires (AgNWs) as the bottom and upper electrodes, and ZnS:Cu as the phosphor layer, respectively. The proposed humidity sensor is based on ACEL with the paper substrate and the ZnS:Cu phosphor layer as the humidity sensing element. The moisture effect on the optical properties of ACELs has been studied firstly. Then, the processing parameters of the paper-based ACELs such as electroless plated bottom electrode and spin-coated phosphor layer as a function of the humidity-sensitive characteristics are investigated. The sensing mechanism of the proposed sensor has been elucidated based on the Q ~ V analysis. The sensor exhibits an excellent linearity ( R 2 = 0.99965 ) within the humidity range from 20% to 90% relative humidity (RH) and shows excellent flexibility. We also demonstrate its potential application in postharvest preservation where the EL light is used for preservation and the humidity can be monitored simultaneously through the current.

scholarly journals Aplikasi Zeolit Alam Aktif Wonosari Sebagai Adsorben Zat Warna Remazol Yellow Fg

2021 ◽  
Vol 1 ◽  
pp. 80-87
Author(s):  
Neni Damajanti ◽  
Anwar Ma’ruf ◽  
Hanafi Khafid Nugraha
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Textile Industry ◽  
Contact Time ◽  
Langmuir Adsorption Isotherm ◽  
Isotherm Model ◽  
Isotherm Models ◽  
Activation Process ◽  
Langmuir Adsorption ◽  
Freundlich Adsorption Isotherm

Zeolite as an adsorbent has been widely used. Zeolite activation was carried out to increase the absorption. This study aimed to determine the characteristics of the active zeolite and apply it as an adsorbent. The activation process was carried out by adding acid and calcining at 4500C for 6 hours. Remazol Yellow FG is a dye that is widely used in the textile industry. In this study, the adsorption process was carried out on the Remazol Yellow FG solution, then analyzed the effect of changes in pH (5, 6, 7, 8, 9), contact time (30, 60, 90, 120, 150 minutes) and the concentration of Remazol Yellow FG solution ( 50, 100, 150, 200, 250 ppm) on the adsorption of Remazol Yellow FG dye. From the analysis of the sample solution of Remazol Yellow, the values of Ce and qe can be calculated. These values were then used to calculate KL and KF in the Langmuir adsorption isotherm and Freundlich adsorption isotherm models. From the experimental results, it could be seen that as the contact time increased, the adsorption capacity would be greater. However, when the zeolite was already in the saturated phase, the adsorption capacity would tend to decrease. In the Langmuir adsorption isotherm, the KL value was 0.0274 L/mg and in the Freundlich adsorption isotherm model, the KF value was 29.25 L/mg. Remazol Yellow FG adsorption tended to follow the Langmuir adsorption isotherm model with an R2 value of 0.998.

Removal of Total Phosphorus from Domestic Wastewater with Clay-Zeolite Medium

2013 ◽  
Vol 647 ◽  
pp. 753-757 ◽  
Author(s):  
Grace K. Luk
Keyword(s):  
Adsorption Isotherm ◽  
Removal Efficiency ◽  
Total Phosphorus ◽  
Contact Time ◽  
Domestic Wastewater ◽  
Scale Model ◽  
Isotherm Model ◽  
Chemical Adsorption ◽  
Solvent Concentration ◽  
Freundlich Adsorption Isotherm

Chemical adsorption of a clay-zeolite pellet medium is being investigated for the removal of total phosphorus from domestic wastewater. The effect of pellet composition, influent concentration, and contact time on the overall removal efficiency is being studied in a five-layer bench-scale model. Results showed that an equilibrium removal of 72% is achieved after a 3 hour contact time, supporting the Freundlich adsorption isotherm model based on the linearization of solute adsorption to equilibrium solvent concentration.

Competitive adsorption of organic solvents using modified and unmodified calcium bentonite clay mineral

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Organic Solvents ◽  
Competitive Adsorption ◽  
Correlation Factor ◽  
Isotherm Model ◽  
Isotherm Models ◽  
High Concentration ◽  
Dual Purpose ◽  
Calcium Bentonite

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene > ethylbenzene > toluene > gasoline > dual purpose kerosene (DPK) > diesel > water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.

scholarly journals Wide range and highly linear signal processed systematic humidity sensor array using Methylene Blue and Graphene composite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Umair Khan ◽  
Gul Hassan ◽  
Rayyan Ali Shaukat ◽  
Qazi Muhammad Saqib ◽  
Mahesh Y. Chougale ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Linear Combination ◽  
Linear Function ◽  
Humidity Sensor ◽  
Sensor Array ◽  
Combination Method ◽  
Humidity Sensing ◽  
Sensing Applications ◽  
Wide Range ◽  
Graphene Flakes

AbstractThis paper proposes a signal processed systematic 3 × 3 humidity sensor array with all range and highly linear humidity response based on different particles size composite inks and different interspaces of interdigital electrodes (IDEs). The fabricated sensors are patterned through a commercial inkjet printer and the composite of Methylene Blue and Graphene with three different particle sizes of bulk Graphene Flakes (BGF), Graphene Flakes (GF), and Graphene Quantum Dots (GQD), which are employed as an active layer using spin coating technique on three types of IDEs with different interspaces of 300, 200, and 100 µm. All range linear function (0–100% RH) is achieved by applying the linear combination method of nine sensors in the signal processing field, where weights for linear combination are required, which are estimated by the least square solution. The humidity sensing array shows a fast response time (Tres) of 0.2 s and recovery time (Trec) of 0.4 s. From the results, the proposed humidity sensor array opens a new gateway for a wide range of humidity sensing applications with a linear function.

scholarly journals Compositional engineering of the pi-conjugated small molecular VOPcPhO : Alq3 complex to boost humidity sensing

RSC Advances ◽  
2017 ◽  
Vol 7 (32) ◽  
pp. 19780-19786 ◽  
Author(s):  
Noshin Fatima ◽  
Fakhra Aziz ◽  
Zubair Ahmad ◽  
M. A. Najeeb ◽  
M. I. Azmeer ◽  
...  
Keyword(s):  
Organic Semiconductor ◽  
Humidity Sensor ◽  
Solution Processed ◽  
Humidity Sensing ◽  
Pi Conjugated ◽  
Hydroxy Quinoline

This study exhibits a solution-processed organic semiconductor humidity sensor based on vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO), tris-(8-hydroxy-quinoline)aluminum (Alq3), and their composites.

scholarly journals Adsorption Study for Trifluralin on Iraqi ? –Alumina

2012 ◽  
Vol 9 (1) ◽  
pp. 153-159 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Adsorption Process ◽  
Kinetic Equations ◽  
Adsorption Study ◽  
Adsorption Capacities ◽  
Experimental Parameters ◽  
Freundlich Adsorption Isotherm ◽  
Equilibrium Adsorption Isotherm

Equilibrium adsorption isotherm for the removal of trifluralin from aqueous solutions using ? –alumina clay has been studied. The result shows that the isotherms were S3 according Giels classification. The effects of various experimental parameters such as contact time, adsorbent dosage, effect of pH and temperature of trifluralin on the adsorption capacities have been investigated. The adsorption isotherms were obtained by obeying freundlich adsorption isotherm with (R2 = 0.91249-0.8149). The thermodynamic parameters have been calculated by using the adsorption process at five different temperature, the values of ?H, ?G and ?S were (_1.0625) kj. mol-1, (7.628 - 7.831) kj.mol-1 and (_2.7966 - _2.9162) kg. k-1. mol-1 respectively. The kinetic study of adsorption process has been studied depending on three kinetic equations: 1- Allergen equation 2- Morris –weber eguation 3- Reichenberg eguation. In general, the result shows the isotherm were on ?- alumina according to Giels classification.? –alumina and thermodynamic

scholarly journals Adsorption Study for Chromium (VI) on Iraqi Bentonite

2010 ◽  
Vol 7 (1) ◽  
pp. 745-756
Author(s):  
Baghdad Science Journal
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Process ◽  
Kinetic Equations ◽  
Bentonite Clay ◽  
Sorption Process ◽  
Adsorption Study ◽  
Chromium Vi ◽  
Freundlich Adsorption Isotherm ◽  
Different Temperatures ◽  
The Subject

The subject of this research involves studying adsorption to remove hexavalent chromium Cr(VI) from aqueous solutions. Adsorption process on bentonite clay as adsorbent was used in the Cr(VI) concentration range (10-100) ppm at different temperatures (298, 303, 308 and 313)K, for different periods of time. The adsorption isotherms were obtained by obeying Langmuir and Freundlich adsorption isotherm with R2 (0.9921-0.9060) and (0.994-0.9998), respectively. The thermodynamic parameters were calculated by using the adsorption process at four different temperatures the values of ?H, ?G and ?S was [(+6.582 ? +6.547) kJ.mol-1, (-284.560 ? -343.070) kJ.mol-1 and (+0.977 ? +1.117) kJ.K-1.mol-1] respectively. This data indicates the spontaneous sorption process. The kinetic study of adsorption process was studied depending on three kinetic equations: 1- Lagergren equation 2- Morris-Weber equation 3- Reichenberg equation

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