No abstract

This work focused on the degradation of toxic organic compounds such as methyl violet dye (MV) in water, using a combined photocatalysis/low pressure reverse osmosis (LPRO) system. The performance of the hybrid system was investigated in terms of the degradation efficiency of MV, COD and membrane separation of TiO2. The aim of the present study was to design a novel solar reactor and analyze its performance for removal of MV from water with titanium dioxide as the photocatalyst. Various operating parameters were studied to investigate the behavior of the designed reactor like initial dye concentration (C = 10-50 mg/L), loading of catalyst (CTiO2 = 200-800 mg/L), suspension flow rate (QL = 0.3-1.5 L/min), pH of suspension (5–10), and H2O2 concentration (CH2O2 = 200-1000 mg/L). The operating parameters were optimized to give higher efficiency to the reactor performance. Optimum parameters of the photocatalysis process were loading of catalyst (400 mg/L), suspension flow rate (0.5 L/min), H2O2 concentration (400 mg/L), and pH = 5. The designed reactor when operating at optimum conditions offered a degradation of MV up to 0.9527 within one hours of operation time, while a conversion of 0.9995 was obtained in three hours. The effluent from the photocatalytic reactor was fed to a LPRO separation system which produced permeate of turbidity value of 0.09 NTU which is closed to that of drinking water (i.e., 0.08 NTU). The product water was analyzed using UV-spectrophotometer and FTIR. The analysis results confirmed that the water from the Hybrid-System could be safely recycled and reuse. It was found that the kinetics of dye degradation was first order with respect to dye concentration and could be well described by Langmuir-Hinshelwood model. A power-law based empirical correlation was developed for the photocatalysis system, related the dye degradation (R) with studied operating conditions.

The palm oil mill effluent imposes environmental issues because of natural and supplement substance. This waste has a significant amount of biological oxygen demand, total suspended solids, chemical oxygen demand, and turbidity. Moringa oleifera seeds' performance analysis as natural coagulants during the pretreatment stage of palm oil mill effluent before it is filtered through commercial nanofiltration membrane is the focus of the current study. The untreated palm oil mill effluent has 2,410 mg/L biological oxygen demand, 3,900 mg/L chemical oxygen demand, 865 NTU turbidity, 41,900 mg/L total suspended solids, and 4.61 pH. The significant reduction occurred in the feed parameters viz., 91.7 % for biological oxygen demand, 83.0 % for chemical oxygen demand, 67.7 % for total dissolved solids, and 72.8 % for turbidity after the pretreatment; however, the pH increased to 4.88. Design expert ® was used to design the experiments and optimize the palm oil mill effluent pretreatment process via a one-factor experimental design. The optimized solution has a 0.994 desirability index. Finally, it was concluded that with ever-tightening environmental standards, moringa oleifera could provide a cheap, green, and potential natural alternative to the existing coagulants employed to treat the palm oil mill effluent.

The aim of the present study was to investigate the optimum operating conditions which yield the best performance of the photocatalysis process for the degradation of the synthetic dye in wastewater. The solar reactor was made up of a flat-plate colorless glass of dimensions of (1000 x 750 x 4 mm). The base of the reactor was made of aluminum. This geometry enables the light entering the liquid film from almost any direction to be reflected and can also be employed for the photocatalytic reaction. Various operating parameters were studied to investigate the behavior of the designed reactor like initial dye concentration (C=10-50 mg/L), loading of catalyst (C TiO2 =300-800 mg/L), suspension flow rate (Q L =0.3-2.0 L/min), pH of solution (5-9), and H 2 O 2 concentration (C H2O2 =200-1000 mg/L). The operating parameters were optimized to give higher efficiency to the reactor performance. Optimum parameters of the photocatalysis process were loading of catalyst (400mg/L), suspension flow rate (0.5L/min), H 2 O 2 concentration (400mg/L), and pH=5. The designed reactor when operating at optimum conditions offered a degradation of MV up to 0.9527 within one hours of operation time, while a conversion of 0.9995 was obtained in three hours. The product water was analyzed using UVspectrophotometer and FTIR. Analysis of the results confirmed that produced water from the solar reactor system could be safely recycled and reuse.

This study was done to determine the quality of water from hand-dug wells in Kuje, Federal Capital Territory Abuja Nigeria. The study area lies between latitudes 080 53’ 24’’N and 080 53’ 47’’N and longitude 070 14’ 24’’E and 070 14’ 35’’E. Water from twenty wells were randomly sampled. The physical properties investigated are pH, temperature, total dissolved solid (TDS) and electrical conductivity. The chemical analysis involved determination of the concentration of anions (SO42-, HCO3-, Fl-, CO3-, Cl-, NO3) and cations (Ca2+, Mg+, Na+,K+, Zn+, Fe2+, Cu2+. A piper diagram based on the relative percentages of the ions was plotted for classification according to hydrogeochemical facies of each water sample based on their dominant ions. The Piper diagram indicated Ca2+ and HCO3- as the dominant ions and therefore it is Ca−HCO3 water type. The physical properties of the water were found to be good based on World Health Organization (WHO) guidelines and National Drinking Water Quality Standard (NDWQS) and therefore water in the study area is safe for human consumption.KEYWORDS: groundwater, hydrochemical facies, anion, cation, piper diagram