Satu kaedah baru bagi pengubahsuaian tanah liat semulajadi, montmorilonit dan bentonit kepada satu siri penjerap berfungsi melalui rawatan kimia telah dilaporkan. Penggunaannya untuk perawatan racun makhluk sekunder, ametryn dan metolachlor, yang selalu diaplikasikan untuk pengawalan serangga perosak, tumbuhan dan kulat telah dikaji. Pengubahsuaian tanah liat telah dijalankan dengan menggunakan rawatan asid dan hexadecyltrimethylammonium bromida (HDTMA), manakala pembolehubah manipulasi telah dikaji menggunakan penjerap berkelompok dengan megubahsuai kepekatan asal, masa sentuhan, dan larutan pH dengan menggunakan kajian kumpulan penjerap. Pemeriksaan ke atas ciri-ciri fizikal dan kimia termasuk morfologi permukaan, sifat-sifat struktur berlubang, permukaan kumpulan berfungsi, dan titik capaian arus sifar (pHzpc) telah dianalisis. Data keseimbangan telah disimulasikan menggunakan model isotherma, Langmuir, Freundlic dan Temkin, manakala model kinetik ditetapkan menggunakan persamaan pseudo-first order, pseudo-second order dan Elovich. Hasil kajian menunjukkan prestasi yang signifikan dalam penyingkiran ametryn dan metolachlor. Penjerapan racun perosak didapati sangat dipengaruhi oleh larutan pH, menjurus penjerapan ametryn dan metalachlor kepada larutan berasid. Peningkatan kepekatan asal dari 25 mg/L kepada 150 mg/L dan 50 mg/L kepada 400 mg/L, menunjukkan peningkatan penjerapan ametryn dari 23.89-132.09 mg/g, 23.36-128.46 mg/g, 12.49- 50.12 mg/g, dan 24.88-148.91 mg/g, untuk montmorillonit, AM, ANC dan AB, manakala penjerapan metolachlor meningkat dari 7.23-38.69 mg/g, 7.32-26.15 mg/g dan 18.45-48.98 mg/g bagi HM, HNC dan AB, masing-masing Penjerapan data keseimbangan mematuhi model Langmuir, manakala model kinetik mengikut persamaan pseudo-second order. Pemeriksaan struktur tekstur mengesahkan pembentukan liang dengan siri berongga di sekitar permukaan, dengan peningkatan jarak kawasan permukaan Brunaeur-Emmet-Teller (BET) dari 2.12 ke 245.64 m2/g. Kajian morfologi menyokong anggapan bahawa interkalasi hexadecyltrimethyammonium bromida (HDTMA) dan proses pengubahsuaian asid telah berjaya dicapai. Pengubahsuaian spektrum Fourier-Transform Infrared Spektroskopi menandakan pengubahsuaian dan pembangunan fungsi baru pada terbitan tanah liat. Hasil kajian mendapati terbitan tanah liat ini mempunyai potensi yang besar sebagai satu penyelesaian ekonomi dan teknik yang mudah untuk pemulihan berterusan air yang dicemari racun makhluk perosak. __________________________________________________________________________________
A new route for the conversion of natural clay, montmorillonite and bentonite into a series of new functionalized adsorbents via simple chemical treatment has been presented. The unique application for the effective remediation of secondary pesticides, ametryn and metalachlor, widely applied for the control of nuisance insects, plants and fungi has been attempted. The clays were subjected to hexadecyltrimethylammonium bromide (HDTMA) and acid modifications, while the novel application was examined using batch adsorption experiments by varying the operational parameters, initial concentration, contact time, and solution pH. The physical and chemical characteristics including the surface morphology, pore structural properties, surface functional groups, and zero-point-of-charge (pHzpc) were evaluated. Equilibrium data were simulated using the Langmuir, Freundlich and Temkin isotherm models, while the kinetic model was fitted to the pseudo-first order, pseudo-second order and Elovich kinetic equations. Result illustrated an encouraging performance towards the removal of ametryn and metolachlor. The adsorptive uptake of pesticides was found to be highly pH dependent, favouring the adsorption uptake of ametryn and metolachlor at the acidic condition. Increasing the initial concentrations from 25 mg/L to 150 mg/L, and 50 mg/L to 400 mg/L showed a greater adsorption uptake for ametryn of 23.89-132.09 mg/g, 23.36-128.46 mg/g, 12.49-50.12 mg/g, and 24.88-148.91 mg/g, for montmorillonite, AM and ANC, and AB, while the adsorption uptake of metolachlor increased from 7.23-38.69 mg/g, 7.32-26.15 mg/g and 18.45-48.98 mg/g, respectively for HM, HNC, and AB. Equilibrium data was satisfactory fitted to the Langmuir isotherm model, while the adsorption kinetic was best described by the pseudo-second order model. Examination of the textural structure verified pore development, with a series of cavities distributed around the surface, with the Brunauer-Emmett-Teller (BET) surface areas ranging from 2.12 to 245.64 m2/g. Morphological study supported the presumption that the intercalation of hexadecyltrimetylammonium bromide (HDTMA) and acid modification process was successfully attained. Alteration of Fourier-transform infrared spectroscopy (FTIR) bands signified the modification and development of the new functionalities on the clay derivatives. The findings supported the great potential of these clay-derivatives as an economically advantageous solution and viable technique for the successive remediation of pesticides contaminated water.
Utilization of natural clay derivatives for the effective treatment of ametryn and metolachlor_Siti Fairos Ab Shattar_REDAC_2017_MYMY