International journal of chemical & material sciences

Spatial distribution of mercury pollution in the Mempawah River Watershed, West Kalimantan – Indonesia

Tri Bayu Aji — 2024-04-07

Mempawah River Basin (DAS) is a water resource for the people of Mempawah and Landak Regencies. The community uses the Mempawah River as the main medium for agricultural needs, plantations, and the rearing of fish for consumption. Awareness of health that comes from water with its various uses, there has been consumer anxiety when consuming air along with agricultural and fishery products that are relevant to water use in the Mempawah watershed. This phenomenon occurs because the water resources of this watershed area have been polluted by mercury as a result of unlicensed gold mining activities in its spatial extent. This research was conducted to analyze the level of mercury pollution in the river basin, due to illegal gold mining activities. The method applied was purposive sampling, through 29 water sample points located in the upstream, middle and downstream. The sample results were explained using the Atomic Absorption Spectroscopy (AAS) tool. Then, from a spatial perspective, the location of PETI activities was analyzed spatially using Spatial Dynamic Modeling Geographical Information System software with kriging interpolation techniques, to predict the distribution of mercury pollution. The results of the research show that in the middle part of the Mempawah watershed, there is mercury pollution from 0.0023mg/lt to 0.0083 mg/l and has exceeded the threshold determined by PP No. 22 of 2021. The upstream and downstream parts of the Mempawah watershed are not polluted by mercury, because the PETI activity point is only in the middle part of the Mempawah watershed. These findings provide suggestions that the allocation of Mempawah River water as the sole raw material for corporate entities and its use for growing fish communities should be more closely monitored, to avoid danger, due to the chain of heavy metal contamination in the form of Mercury.

Response surface methodology for the production of a filter membrane from the combination of sand, PET and salt as a pore-forming agent

Nathalie Laure Tchuisseu Minkla — 2024-08-14

Plastic waste is increasing every day due to urbanization, population growth and in turn, pollutes the environment. These wastes are considered to be a big problem due to their very low biodegradability and presence in large quantities. A large amount of plastic which is being brought by human activities is discarded or burned which leads to the contamination of the environment and air. Therefore, finding alternative methods of disposing of waste by using kind approaches is becoming a major research issue. In this research, polyethene terephthalate waste is used as a binder by burning and mixing with sand and sodium carbonate to investigate the possibility of producing composite material with a plastic sand filter and study the effect of sand, polyethene terephthalate waste and porogen with different design mix ratio on the properties of the product. An experimental design plan was adopted to formulate the materials. To fabricate this material, the melt moulding/particulate leaching technique was used, in which the components are mixed in their respective proportions, moulded, melted and afterwards leached to remove the porogen. We obtained an optimum of 31.0711% porosity for the optimum mixture containing proportions of 0.5, 0.25 and 0.25 plastic sand and porogen respectively. An improved melt/moulding particulate leaching technique was used to improve the permeability and reduce pore sizes of the optimum. This technique involved using a saturated solution of porogen instead of using the porogen in particulate form. The microbial cut-off efficacy of the material was evaluated, in which microbiological analyses were used to enumerate the number of microbes in a lake water sample before and after filtration through the porous material. The results of viable cell counting showed that the material eliminated 92.6% of the water microbes analysed.