Judul: Adsorpsi Ion Cu(II) oleh Kitosan Bertaut Silang Tripolifosfat
Abstrak: Kitosan bertaut silang tripolifosfat (kitosan-TPP) dapat digunakan untuk mengadsorpsi ion Cu(II). Taut silang dengan TPP pada kitosan dapat menstabilkan dan meningkatkan kapasitas adsorpsi. Tujuan penelitian ini adalah menganalisis kondisi optimum, kapasitas adsorpsi, dan isoterm adsorpsi larutan kitosan bertaut silang dengan TPP terhadap ion Cu(II) sehingga mekanisme adsorpsinya dapat diketahui. Adsorpsi ion Cu(II) dilakukan melalui sistem batch. Kondisi optimum ditentukan melalui metode permukaan respon dan digunakan untuk menentukan model isoterm adsorpsi. Hasil karakterisasi kitosan-TPP menggunakan spektrofotometer transformasi Fourier menunjukkan serapan dari P=O pada bilangan gelombang 1246 cm-1, serta dua serapan baru pada bilangan gelombang 1632 cm-1 dan 1589 cm-1 vibrasi tekuk N-H. Butiran kitosan-TPP memiliki waktu kontak yang lebih singkat (39.54 menit) untuk menjerap ion Cu(II) daripada butiran kitosan (140 menit). Kapasitas adsorpsi Cu(II) oleh butiran kitosan-TPP nilainya tidak jauh berbeda dibandingkan dengan butiran kitosan. Isoterm adsorpsi butiran kitosan-TPP mengikuti model isoterm Freundlich.
Keyword: gelasi ionik, isoterm adsorpsi, kitosan, tripolifosfat

Judul: Adsorben Kitosan Bertaut Silang Glutaraldehida sebagai Penjerap Ion Cu(II).
Abstrak: Kitosan dapat digunakan sebagai biopolimer yang bermanfaat untuk menjerap ion logam berat. Tujuan penelitian ini adalah membandingkan kapasitas adsorpsi dari adsorben kitosan beads dan kitosan bertaut silang glutaraldehida sebagai penjerap ion Cu(II). Pencirian adsorben menggunakan spektrofotometer transformasi Fourier menunjukkan serapan gugus C=N dan C=O pada bilangan gelombang 1618.28 dan 1786.08 cm-1. Optimasi dengan sistem adsorpsi tumpak menggunakan metode permukaan respons dengan 3 parameter, yaitu konsentrasi larutan awal ion Cu(II), waktu kontak, dan bobot adsorben. Hasil penelitian menunjukkan bahwa besarnya nilai kapasitas adsorpsi kitosan bertaut silang glutaraldehida terhadap ion Cu(II), tidak jauh berbeda dengan kitosan beads tetapi berdasarkan waktu kontaknya, adsorben kitosan bertaut silang glutaraldehida lebih cepat menjerap ion Cu(II) dibandingkan dengan kitosan beads. Adsorpsi isoterm menunjukkan kedua adsorben mengikuti tipe Freundlich.
Keyword: glutaraldehida, isoterm adsorpsi, kitosan

Judul: Spatial Model of Developing Village Based on Road Network and Land Use in Brebes District
Abstrak: Brebes is a rural district dominated by agricultural areas. The area of Brebes Regency is 1,769.62 km2 consisting of 292 villages and 17 sub-districts. Brebes Regency is in the northern region of Central Java Province, borders West Java, and is traversed by the Pantura National Road and the Trans-Java toll road. Geographically, the location of Brebes Regency is strategic so that infrastructure development is expected to optimize geographical advantages and encourage socio-economic development. However, in fact the gross regional domestic product (GRDP) per capita in Brebes in 2022 is IDR 17.61 million lower than the average GRDP per capita in the former Pekalongan Residency districts (consisting of five districts namely Pekalongan, Tegal, Pemalang, Batang, and Brebes) amounting to IDR 22.02 million. The Human Development Index of Brebes is 67.03, the lowest in Central Java, and the poverty rate in 2022 is 16.05%, the third highest in Central Java. Another indicator in assessing the development of Brebes, according to its characteristics which are dominated by rural areas, is the Village Development Index (IDM). IDM is a village development assessment index compiled by the Ministry of Villages, Disadvantaged Regions and Transmigration. IDM is a com-posite index that assesses social resilience, economic resilience and environmental resilience. Brebes' IDM in 2022 is 0.6850 or on average they have developing village status. The value is below the Central Java’s IDM average (0.7118) and below the IDM average of the former Pekalongan Residency districts (0.6913). To overcome backwardness, it is necessary to study the spatial aspects of rural areas in Brebes Regency so that rural development can be in harmony with the spatial factors that most influence each village. The main objective of this research is to create modeling based on spatial factors in the form of road networks and land use on the level of village development in Brebes Regency. The method used is road network analysis and land use analysis, as well as regression analysis to determine the influence of the road network and land use on the IDM of Brebes Regency. The selected road network analysis is an analysis of road connectivity (alpha and beta indices), road density, and shortest route, while the land use analysis selected is an analysis of built-up land, regional compactness, and land use diversity. Both analyzes produce quantitative data which is used as an independent variable to assess village development based on IDM as the dependent variable. Correlation between variables was analyzed through geographically weighted regression (GWR) which was preceded by ordinary least squares (OLS) analysis accompanied by a com-parison of the two. The first stage of road network analysis produces an alpha index, beta index, and road network density level. The alpha index value in Brebes is in the range 0.370-0.856 with an average value of 0.455. This figure is still lower than the perfect score (α=1), which means that the road network in Brebes within the village area is not fully connected well. Meanwhile, the beta index value in Brebes is in the interval 1.682-1.944 with an average value of 1.792. This figure means that the road network
Keyword: GWR, road network, land use, village development