Parasetamol dan tetrasiklin terkenal dari segi penggunaan serta pengeluaran tahunan yang amat tinggi di seluruh dunia. Kehadiran kedua-dua bahan farmaseutikal ini di dalam pelbagai jenis sumber air telah dilaporkan di negara yang berlainan. Dalam kajian ini, pencirian air kumbahan telah membuktikan bahawa loji rawatan kumbahan konvensional berkesan dalam degradasi parameter konvensional ke tahap yang selamat, namun ia tidak berupaya untuk menyingkirkan sisa farmaseutikal (seperti parasetamol dan tetrasiklin) yang muncul di dalam air sisa kumbahan. Selain itu, kajian ini menyelidik keberkesanan proses rawatan fotopemangkin heterogen titanium dioksida [TiO2]/suria dalam penyingkiran parasetamol dan tetrasiklin dari air sisa sintetik secara berasingan. Kesan dari setiap pembolehubah yang dipilih (tempoh pendedahan terhadap cahaya matahari, pH, kepekatan TiO2 dan kepekatan farmaseutikal) dalam proses rawatan fotopemangkin telah dikenalpasti dengan menggunakan kaedah pemboleh ubah tunggal pada satu masa (SVAT). Hasil kajian menunjukkan bahawa semua pembolehubah yang dipilih mempengaruhi kecekapan penyingkiran parasetamol dan tetrasiklin. Seterusnya, rekaan pusat rencam (CCD) berdasarkan kaedah permukaan sambutan (RSM) telah digunakan untuk mengoptimumkan pembolehubah bagi kepekatan TiO2 dan farmaseutikal. Penyingkiran parasetamol sebanyak 82% diperolehi dalam keadaan optimum 1.0 g/L kepekatan TiO2 dan 0.06 g/L kepekatan parasetamol, manakala sebanyak 75% tetrasiklin telah disingkirkan dalam keadaan optimum 2.64 g/L kepekatan TiO2 dan 0.07 g/L kepekatan tetrasiklin. Akhir sekali, kinetik degradasi fotopemangkin parasetamol dan tetrasiklin didapati mematuhi kinetik model Langmuir-Hinshelwood. Pemalar kadar (k) dan pemalar jerapan (K) dalam proses degradasi fotopemangkin parasetamol dan tetrasiklin masing-masing adalah 0.00052 g/L.min, 131.58 L/g dan 0.0028 g/L.min, 71.43 L/g. Hasil kajian ini telah membuktikan kebolehpercayaan cahaya suria sebagai sumber UV semulajadi dalam proses degradasi fotopemangkin. __________________________________________________________________________________
Paracetamol and tetracycline are well known with tremendous annual worldwide production and high global consumption rate. Their occurrence in the various water compartments has been reported in different countries. In this study, sewage characterization showed that the conventional wastewater treatment plant was effective to degrade the conventional parameters to the acceptable conditions, but it was unable to remove the pharmaceutical compounds (paracetamol and tetracycline) appeared in the sewage treatment plant (STP). Next, this study investigated the performance of heterogeneous photocatalysis titanium dioxide [TiO2]/solar treatment process in removing the paracetamol and tetracycline individually from the synthetic wastewater. In the batch study, the effects of the selected variables (sunlight exposure period, pH, TiO2 concentration and initial concentration of pharmaceutical) on the photocatalytic degradation efficiencies of paracetamol and tetracycline were investigated by using the single-variable-at-a-time (SVAT) method. Results showed that all of these selected factors greatly affected the removal efficiencies of paracetamol and tetracycline. Next, central composite design (CCD) based on the response surface methodology (RSM) were used to optimize the TiO2 and pharmaceutical concentrations. Under the optimum conditions of 1.0 g/L of TiO2 concentration and 0.06 g/L of initial concentration of paracetamol, around 82% of paracetamol removal efficiency was attained, whereby, approximately 75% of tetracycline removal efficiency was achieved under the optimum conditions of 2.64 g/L of TiO2 concentration and 0.07 g/L of initial concentration of tetracycline. Finally, the kinetic of the photocatalytic degradation of paracetamol and tetracycline fitted well with the Langmuir-Hinshelwood kinetic model. The reaction rate constant (k) and adsorption constant (K) for the photocatalytic degradation process of paracetamol and tetracycline were 0.00052 g/L.min, 131.58 L/g and 0.0028 g/L.min, 71.43 L/g, respectively. The results from these in situ experiments have proven the reliability of the solar in the photocatalysis treatment process.
Removal of paracetamol and tetracycline from synthetic wastewater using heterogeneous tio2 solar photocatalyst_Lee Chee Mei_A9_2017_MYMY