scholarly journals Synthesis of a Layered Organic-Inorganic Nanohybrid of 4-Chlorophenoxyacetate-zinc-Layered Hydroxide with Sustained Release Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Mohd Zobir Hussein ◽  
Nor Farhana binti Nazarudin ◽  
Siti Halimah Sarijo ◽  
Mohd Ambar Yarmo
Keyword(s):  
Active Agent ◽  
Grain Structure ◽  
Aqueous Environment ◽  
Direct Reaction ◽  
Atmospheric Conditions ◽  
Variable Size ◽  
Release Formulation ◽  
Pure Phase ◽  
Pseudo Second Order ◽  
Zinc Layered Hydroxide

A zinc-layered hydroxide-4-chlorophenoxy acetate (4CPA) organic-inorganic nanohybrid was prepared using a simple direct reaction of 4CPA anions with ZnO under an aqueous environment to be used as a controlled release formulation of the herbicide, 4CPA. The concentration of the active agent, 4CPA, was found to be a controlling factor for the formation of a pure phase well-ordered nanolayered hybrid in which it could be synthesised at 0.2 M 4CPA. ZnO shows a well-defined grain structure of variable size in the nanometre range. However, the formation of the 4CPA-ZLH nanohybrid resulted in a flake-like fibrous structure. On heating at 500°C for 5 h under atmospheric conditions, the nanohybrid transformed back to a well-defined grain structure, as previously observed with the starting material, ZnO. The release of 4CPA was found to occur in a controlled manner and was generally governed by pseudo-second-order kinetics.

Synthesis and Physico-Chemical Properties of Zinc Layered Hydroxide-3-4-Dichlorohenoxy Acetic Acid (ZLH34D) Nanocomposite

2017 ◽  
Vol 744 ◽  
pp. 441-445
Author(s):  
Norhafiza Mohd Salleh ◽  
Siti Halimah Sarijo ◽  
Anizah Kalam
Keyword(s):  
Acetic Acid ◽  
Chemical Properties ◽  
Granular Structure ◽  
Basal Spacing ◽  
Aqueous Environment ◽  
Direct Reaction ◽  
Physico Chemical ◽  
Pure Phase ◽  
Zinc Layered Hydroxide ◽  
Dichlorophenoxy Acetic Acid

A herbicide, 3,4-Dichlorophenoxy acetic acid (34D) was successfully intercalated into the zinc layered hydroxide (ZLH) by direct reaction with zinc oxide (ZnO) to form a new organic-inorganic zinc layered hydroxide-3,4-Dichlorophenoxy acetate (Z34D) under an aqueous environment. The pH of the solution was adjusted to 7.5 using 2 M sodium hydroxide (NaOH). The pure phase and well-ordered was synthesized at 0.3 M Z34D. PXRD patterns show well-ordered nanohybrid material with basal spacing at 26.1 Å. The percentage loading of 34D in the Z34D is 57.5 % (w/w) calculated based on the percentage of carbon in the sample. FESEM shows the ZnO precursor has very fine granular structure and transformed into agglomerate structure when the nanohybrid are formed. This work shows that the nanohybrid of Z34D can be synthesized using simple, direct-reaction method.

scholarly journals Studies on Highly Dense Pure YIG Polycrystalline Ceramics Fabricated by Tape-casting Method

2020 ◽  
Author(s):  
Chong Zhao ◽  
Yingkui Li ◽  
Xiaofei Shen ◽  
Zhijun Cao ◽  
Zhiquan Cao ◽  
...  
Keyword(s):  
Tape Casting ◽  
Solid State Reaction Method ◽  
Grain Structure ◽  
Casting Method ◽  
Forming Process ◽  
Sem Images ◽  
Polycrystalline Ceramics ◽  
Pure Phase ◽  
One Step ◽  
Xrd Patterns

Abstract Pure phase Y3Fe5O12 (YIG) ceramics was successfully produced by tape-casting forming process and one-step solid-state reaction method. With the sintering temperature above 1100 ºC, the pure phase YIG ceramics was synthesized with no YIP or Fe2O3 phase in XRD patterns. YIG ceramic sintering at 1400 ºC for 10 h showed a clear grain structure with an obvious grain boundary, and no pores were observed in the SEM images. YIG ceramics in this paper has a high relative density which was 99.8% and the saturation magnetization was 28.2 emu/g at room temperature. The hysteresis loss at temperatures of 230-360 K was smaller than 10 mJ/kg. The tan Se was nearly zero at 6~7 GHz and 11~12 GHz, showing that it can be used as a good material for microwave applications. In addition, the low values of tan and tan indicates that it may have a good electromagnetic wave absorption ability.

scholarly journals Controlled release formulation of an anti-depression drug based on a L-phenylalanate-zinc layered hydroxide intercalation compound

2017 ◽  
Vol 105 ◽  
pp. 35-44 ◽  
Author(s):  
Norhayati Hashim ◽  
Sharifah Norain Mohd Sharif ◽  
Illyas Md Isa ◽  
Shahidah Abdul Hamid ◽  
Mohd Zobir Hussein ◽  
...  
Keyword(s):  
Controlled Release ◽  
Intercalation Compound ◽  
Release Formulation ◽  
Controlled Release Formulation ◽  
Zinc Layered Hydroxide

Nanoclay-Supported Zero-Valent Iron as an Efficient Adsorbent Material for Arsenic

2013 ◽  
Vol 686 ◽  
pp. 296-304 ◽  
Author(s):  
Michael Leo Dela Cruz ◽  
Khryslyn Araño ◽  
Eden May Dela Pena ◽  
Leslie Joy L. Diaz
Keyword(s):  
Inductively Coupled Plasma ◽  
Order Rate Constant ◽  
Interplanar Distance ◽  
Second Order ◽  
Zero Valent Iron ◽  
Particle Model ◽  
Aqueous Environment ◽  
Arsenic Adsorption ◽  
Elovich Equation ◽  
Pseudo Second Order

The release of arsenic to aqueous environment imposes threats to human health. Montmorillonite supported zero-valent iron (ZVI-MMT) is a material with capability of immobilizing arsenic from aqueous environment. The arsenic adsorption efficiency of ZVI-MMT was obtained. In addition, adsorption kinetics of arsenic contaminated water on the material was determined. Arsenic and iron content was quantified by an inductively coupled plasma mass spectrometer (ICP-MS), interplanar distance of the adsorbent was measured by x-ray diffractometer (XRD), and the morphology of the adsorbent was obtained from a transmission electron microscope (TEM). Isotherm data were analyzed using the Langmuir and Freundlich isotherms. The data fitted well to Langmuir isotherm with derived adsorption capacity of 20.1 mg/g. Kinetics data were analyzed using intra-particle model, Elovich equation, pseudo first-, and pseudo second-order models. Elovich equation and pseudo second-order equation fitted the experimental data with pseudo second-order rate constant of 61.2 x 10-4 g/mg-min.

scholarly journals Herbicide-Intercalated Zinc Layered Hydroxide Nanohybrid for a Dual-Guest Controlled Release Formulation

2012 ◽  
Vol 13 (6) ◽  
pp. 7328-7342 ◽  
Author(s):  
Mohd Zobir Hussein ◽  
Nor Shazlirah Shazlyn Abdul Rahman ◽  
Siti H. Sarijo ◽  
Zulkarnain Zainal
Keyword(s):  
Controlled Release ◽  
Release Formulation ◽  
Controlled Release Formulation ◽  
Zinc Layered Hydroxide

scholarly journals Adsorption of Zn(II) ions from aqueous environment by surface modified Strychnos potatorum seeds, a low cost adsorbent

2013 ◽  
Vol 15 (3) ◽  
pp. 35-41 ◽  
Author(s):  
P. Senthil Kumar
Keyword(s):  
Experimental Data ◽  
Low Cost ◽  
Agricultural Waste ◽  
Coefficient Of Determination ◽  
Aqueous Environment ◽  
Freundlich Model ◽  
Shrinking Core ◽  
Pseudo Second Order ◽  
Strychnos Potatorum ◽  
Surface Modified

Abstract The surface modified Strychnos potatorum seeds (SMSP), an agricultural waste has been developed into an effective adsorbent for the removal of Zn(II) ions from aqueous environment. The Freundlich model provided a better fit with the experimental data than the Langmuir model as revealed by a high coefficient of determination values and low error values. The kinetics data fitted well into the pseudo-second order model with the coefficient of determination values greater than 0.99. The influence of particle diffusion and film diffusion in the adsorption process was tested by fitting the experimental data with intraparticle diffusion, Boyd kinetic and Shrinking core models. Desorption experiments were conducted to explore the feasibility of regenerating the spent adsorbent and the adsorbed Zn(II) ions from spent SMSP was desorbed using 0.3 M HCl with the efficiency of 93.58%. The results of the present study indicates that the SMSP can be successfully employed for the removal of Zn(II) ions from aqueous environment.

scholarly journals The sorption of Tebuconazole and Linuron from an Aqueous Environment with a Modified Sludge-Based Biochar: Effect, Mechanisms, and Its Persistent Free Radicals Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jingjie Yang ◽  
Hongwei Sun ◽  
Yucan Liu ◽  
Xiaohan Wang ◽  
Kamran Valizadeh
Keyword(s):  
Free Radicals ◽  
Kinetic Equations ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Contributing Factors ◽  
Freundlich Model ◽  
Preparation Conditions ◽  
Short Period ◽  
Spin Resonance ◽  
Pseudo Second Order

In this study, the sludge-based biochar was prepared and utilized as an adsorbent for the removal of two commonly used pesticides in agriculture, namely tebuconazole (Teb) and linuron (Lin) in an aqueous solution. The main contributing factors such as biochar preparation conditions, persistent free radicals as well as contact time, agitation speed, biochar dose, temperature, and pH were investigated. The physicochemical properties were characterized by SEM + EDS, FTIR, BET, EPR, etc. The results showed that the maximum adsorption capacities based on the Langmuir model was 7.8650 mg g−1 for tebuconazole and that based on Freundlich model was 9.0645 mg·g-1 for linuron at 25°C. The pseudo-second-order kinetic equations were all fitted well to the kinetic process of the adsorption of the two pesticides with all R2 ≥ 0.915. The maximum values of tebuconazole adsorption capacity occur at pH = 3. Meanwhile, linuron was not affected by pH. Both Cr6+ (r = −0.793∗∗/ −0.943∗∗) and humic acid (r = −0.798∗∗/ −0.947∗∗) significantly inhibited the adsorption amount of tebuconazole and linuron onto the biochar. Electron spin resonance signals (ESR) indicated that environmentally persistent radicals (EPFRs) are preferentially formed at lower pyrolysis temperatures and lower transition metal concentrations. The g-factors for BC400, BC600, BCF400, and BCF600 were 2.0036, 2.0035, 2.0034, and 2.0033, respectively, indicating that the EPFRs mainly have a carbon-centered structure with adjacent oxygen atoms. In addition, to close to the actual situation, natural water (from YanTai) was collected to simulate pesticide contamination. This study demonstrates that sludge-based biochar can achieve efficient removal of tebuconazole and linuron in aqueous environment in a short period of time with no secondary environmental risk especially on the waste activated sludge.

scholarly journals Fluoride and Arsenite Removal by Adsorption on La2O3-CeO2/Laterite

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Duong Thi Lim ◽  
Trinh Ngoc Tuyen ◽  
Dao Ngoc Nhiem ◽  
Dao Hong Duc ◽  
Pham Ngoc Chuc ◽  
...  
Keyword(s):  
Piecewise Linear ◽  
Nitrogen Adsorption ◽  
Aqueous Environment ◽  
Piecewise Linear Regression ◽  
Intraparticle Diffusion Model ◽  
Binary Oxides ◽  
Fluoride Adsorption ◽  
Pseudo Second Order ◽  
Arsenite Removal ◽  
Adsorption Desorption

In the present article, the adsorbent prepared from laterite with lanthanum and cerium oxides (La2O3-CeO2/laterite (LCL)) was efficiently employed for the removal of arsenite and fluoride from an aqueous environment. The obtained materials were characterized by XRD, SEM, and nitrogen adsorption/desorption. The synthesized LCL exhibited a high adsorption capacity towards arsenite (As(III)) and fluoride. The adsorption of both analytes on LCL, which was well-fitted to a pseudo-second-order equation, was found to be kinetically fast in the first 20 minutes and reached equilibrium at around 180 minutes. Weber’s intraparticle diffusion model in multilinearity using the piecewise linear regression combined with Akaike’s criteria was addressed. The adsorption capacities of LCL calculated from Langmuir’s isotherm model were found to be 67.08 mg·g-1 for arsenite and 58.02 mg·g-1 for fluoride. Thermodynamic parameters presented an endothermic nature of arsenite adsorption but an exothermic nature for fluoride and a negative Gibbs free energy for the spontaneous process of arsenite or fluoride adsorption at the studied temperature range. The excellent adsorption performance and stability make the composite of laterite and La-Ce binary oxides an alternative efficient and cheap adsorbent for the removal of arsenite and fluoride in an aqueous solution.

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