Due to the lack of studies regarding the potential of polyvinylpyrrolidone (PVP) as capping agent in precipitation of zinc oxide (ZnO) nanoparticles, this research focused on the performance of ZnO nanoparticles with presence of PVP loading on photocatalytic degradation treatment for industrial dye wastewater. Three different samples of ZnO-PVP were successfully synthesized via precipitation method. The degradation rate of dye approached 90.61% under pH7 in the presence of ZnO-PVP (0.025g/L of PVP). The chemical bonds in ZnO-PVP was analysed using Fourier Transform Infrared Spectroscopy (FTIR).

High amount of heavy metal waste produced from the industrial activities has become an important global issue for several decades due to its hazardous effect on the human and environment. Since heavy metal is highly toxic and cannot be eliminated easily, the application to reuse the heavy metal waste without harming the environment must be investigated thoroughly. This paper reviews the incorporation of heavy metal into clay precursors as a good potential for the reduction of environmental pollution. The results from the previous studies show the transformation of heavy metal such as copper, zinc, lead and cadmium into less hazardous species when incorporating into clay precursors. These transformations have reduced the mobility of heavy metal as a crystalline structure is formed after the thermal treatment. It is found that the immobilization process successfully stabilizing heavy metal and increases the metal’s resistance against the acidic attack through the formation of low permeable structure in the clay precursors. Hence, the incorporation of heavy metal into clay precursors is proven to be a great prospect in reducing environmental pollution.

Lake water getcontaminate due to the growth of population and modernization which causing problems like sewage disposal has a high-volume and low-strength wastewater that can be reused for many purposes after being treated. It is crucial for wastewater to go through wastewater treatment to improves the quality of water where one of the processes involved is coagulation yet using conventional coagulant leaves excess heavy metal in the water causes in the absence of green chemistry. Chemical coagulants may have an adverse effect on the consumer and the environment such as aluminum build up in the environment, as well as have a harmful influence on the human body, resulting in Alzheimer's disease. The use of natural coagulants can be a secure replacement for chemical coagulants. Therefore, this study was conducted to reduce the usage of chemicals in the coagulation process by using natural coagulant of banana peels and soybean hulls. The main aim of this study is to investigate the effect of natural coagulant for wastewater treatment of lake water. Banana peels and soybean hulls were the main materials in making a plant-based coagulant by drying, grinding, and sieving. Jar test was carried out to investigate the effectiveness of natural coagulant by determining their turbidity and total suspended solids.It was found that banana peels perform effectively at a dosage of 400mg/L with turbidity removal achieved is almost 50%. On the other hand, soybean hulls work effectively at a dosage of 600mg/L with turbidity removal achieved is 54%. Based on the result, it is shown that using banana peels as a natural coagulant has effectively reduced the turbidity and total suspended solids of lake water with the optimum number of dosages of 600mg/L.