Ce⁴⁺-doped nanometer ZnO powder was synthesized by so-l gel method. The microstructures and properties of the samples were characterized through XRD, UV-Vis and FTIR. The results indicated that the Ce⁴⁺ was successfully incorporated into ZnO, and the diameter of the nanometer was about 10.7nm. It induced the redshifting in the UV-Vis spectra. The photocatalytic activity of the samples was investigated using methylene blue (MB) as the model reaction under irradiation with ultraviolet light. The results showed that the doping of Ce⁴⁺ could increase the photocatalytic activities of ZnO nanopowders and that the best molar ratio of Ce⁴⁺ was n(Ce)/n(Zn) = 0.05, that the surfactant was sodium dodecyl sulfate, and that the nanometer ZnO was calcinated at 550 ℃ for 3 hours. Meanwhile, it inspected the effect of photocatalytic efficiency through the pH of MB, the amount of catalyst, and illumination time. The experimental results revealed that the initial mass concentration of MB was 10 mg/L, that the pH value was 7-8, that the dosage of Ce⁴⁺/ZnO photo-catalyst was 5 g/L, that the UV-irradiation time was 2 h, and that the removal rate of MB reached above 85%. Under the optimized conditions, the degradation rate of real dye wastewater was up to 87.67% and the removal efficiency of COD was 63.5%.

This study was carried out at the Teaching and Research Farm of Landmark University, Omu-Aran. Treatments consisted of 3 levels of cocoa pod husk ash (0, 2 and 4 tonnes CPHA ha^-1), 3 levels of cocoa pod husk powder (0, 2 and 4 tonnes CPHP ha^-1), NPK and the control. The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated four times. The following parameters were taken plant height, number of leaves (at 2, 3, and 4 weeks after sowing), total plant weight, root weight, leaf weight, roots girth and roots length. Data collected were subjected to Analysis of Variance (ANOVA) Using S.A.S, 2000. Treatment means were compared using Duncan Multiple Range Test (DMRT) at 0.05 level of probability. Results showed that chemical analysis of cocoa pod ash and powder contained plant nutrients as N, P, K, Ca, Mg and some other micronutrients in varying proportions. Application of CPHA 4 + CPHP 2 gave higher values for all the vegetative parameters. The implication of this study is that high level of cocoa pod husk powder in combination with high level of cocoa pod husk ash is detrimental to radish cultivation. In the same vein, the nutrition of radish was incomplete when NPK fertilizer was applied. It can therefore be recommended that the use of combined application of cocoa pod ash and cocoa pod powder at CPHA4 + CPHP2 was sufficient for the cultivation of radish (Raphanus sativus) in the study area as it compete favorably with application of NPK fertilizer.