Adsorption Configurations of Iron Complexes on As(III) Adsorption Over Sludge Biochar Surface

Waste recycling and reuse will result in significant material and energy savings. In this research, usage of hospital sludge as a biochar adsorbent for wastewater treatment plants was investigated. Microwave carbonization was used to carbonize the sludge and then chemically activated with ZnCl2to increase surface area and porosity. A newly designed iron metal doped sludge biochar carbon (SBC) has effective adsorption of inorganic arsenic (As(III), As2O3) in water. The findings clearly demonstrate the viability and utility of using hospital sludge as a source of carbon to generate SBC. The adsorption mechanism of As(III) on SBC’s iron-metal-modified surface has been studied using density functional theory (DFT) to understand the impact of functional complexes on adsorption As(III). Tests showed physical as well as chemical adsorption of As(III) on Fe-SBC surface. Fe’s involvement in functional complexes greatly fostered SBC surface activity and it’s As(III) adsorption ability. The physical adsorption energies of As(III) with Fe functional complexes on the SBC surface were −42.3 KJ mol−1. Other hand, the chemical adsorption energies of As(III) on Fe-SBC surface was −325.5 KJ mol−1. As(III) is capable of interacting in a bidentate fashion with the dopants through the protonated oxygen atoms and this conformation of the cyclic structure is higher in the adsorption energy than the others.

Efektivitas Komposit Material Overburden Batubara, Zeolit, dan Arang Aktif Tempurung Kelapa Sebagai Adsorben Besi dalam Air Asam Tambang

Abstrak: Penelitian ini mempelajari penyerapan Fe dari air asam tambang yang berasal dari lokasi penambangan batubara. Adsorben yang digunakan dalam penelitian ini yaitu kombinasi antara claystone, zeolit, dan arang aktif tempurung kelapa. Adsorben tersebut harus diaktivasi terlebih dahulu untuk membersihkan pengotor di permukaannya sehingga luas permukaannya meningkat. Aktivasi claystone dilakukan dengan 3M NaOH, zeolit dengan 3M HCl, dan arang tempurung kelapa dengan 4M HCl. Komposit dibuat dengan mencampurkan ketiga adsorben dengan perbandingan (Claystone[C]: Zeolit[Z]: Arang aktif[A]) = 25:25:50. Hasil uji luas permukaan menunjukkan bahwa komposit memiliki luas permukaan 62,44 m2/g. Adsorpsi dilakukan dengan sistem batch menggunakan alat hot plate stirer pada variasi waktu kontak 30, 60, 90, 120, dan 150 menit. Berdasarkan hasil uji adsorpsi, 7,5 gram komposit mampu menurunkan konsentrasi Fe dengan efektivitas 99,61% dan kapasitas adsorpsi 0,432 mg/g pada waktu kontak 30 menit. Kata Kunci: adsorpsi, komposit, efektivitas, kapasitas Abstract: This research studied adsorption iron (Fe) from acid mine drainage in coal mining. Adsorbent used in this research is the combination of activated claystone, activated zeolite, and ativated carbon from coconut shell. The adsorbents need to be activated to remove the impurities from its surface and improved its surface area. Claystone was activated using 3M NaOH, 3M HCl for zeolite, and 4M HCl for coconut shell. Composite was made by mixing claystone, zeolite, and coconut shell with 3 ratio (claystone [C], zeolite [Z], activated carbon [A]) = 25:25:50. The result of surface area analyzer showed that the surface area of composite was 62,44 m2/g. Adsorption with batch system was carried out using hot plate stirer on 30,60, 90, 120, and 150 minutes of contact time. Adsorption result showed that 7,5 gram of composite succeded decreasing iron metal concentration with 99,61% effectiveness and 0,432 mg/g adsorption capacity on 30 minutes of contact time. Keywords: adsorption, composite, efectiveness, capacity

Tetracarbonate melts and the fate of primordial carbon in the deep Earth

Much of Earth’s carbon is thought to have been stripped away from the silicate mantle by dense metallic-iron to form the core1. However, recent studies2,3 suggest that a considerable part of it could have remained stranded in the deep mantle due to a change in its affinity to dissolve into iron metal-alloys at the extreme pressures and temperatures of the deep Earth. The underlying physical phenomena that would render carbon less siderophile at extreme conditions remain elusive. Here we describe the compaction mechanisms and structural evolution of a simple carbonate glass to deep mantle pressures by monitoring the evolution of the electronic state and atomic structure of the glass upon compression. Our new experiments demonstrate a pressure-induced change in hybridization of carbon from sp2 to sp3 starting at 40 GPa, due to the conversion of [3]CO32- groups into [4]CO44- units, which is completed at ~112 GPa. The pressure-induced increase of carbon coordination number from three to four increases possibilities for carbon-oxygen interactions with lower mantle silicates and increased compatibility4,5. Tetracarbonate melts provide a mechanism for changing the presumed siderophile nature of deep carbon and instead imply storage of carbon in the deep mantle as a possible source for carbon-rich emissions registered at the surface in intra-plate and near-ridge hot spots6,7

RADICAL INITIATED COPOLYMERIZATION OF METHYL METHACRYLATE AND ACRYLONITRILE IN PRESENCE OF IRON COMPLEXES

This article represents data on the effect of organometallic iron complexes: ferrocene, dicarbonyl dimer of cyclopentadienyl iron and tricarbonyl cyclooctatetraene iron on the copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) initiated by benzoyl peroxide. It is shown that the introduction of metal complexes and their structure affect the initial rate of copolymerization, the form of the diagrams of the composition of the obtained copolymers, and the values of the effective constants of the relative activities of the comonomers in the copolymerization of methyl methacrylate and acrylonitrile (system metallocomplex of iron – peroxide benzoyl: ferrocene – peroxide benzoyl: rММА = 1.58; rАН= 0.08 in 60 °С; rММА = 1.30; rАН = 0.05 in 50 °С; dicarbonyl dimer cyclopentadienyl iron–peroxide benzoyl: rММА = 1.36; rАН = 0.06 in 60 °С; rММА = 1.09; rАН = 0.14 in 50 °С; tricarbonyl cyclooctatetraene iron -peroxide benzoyl: rММА = 1.08; rАН = 0.15 in 60 °С; rММА = 1.14; rАН = 0.05 in 50 °С; peroxide benzoyl: rММА = 1.11; rАН = 0.07 in 60 °С; rММА = 1.11; rАН = 0.07 in 50 °С). The proportions of triadic sequences of units in copolymers, experimentally determined from 1H NMR spectroscopy, are given, as well as the calculated proportions of dyads. The presence of iron metal complexes affects the distribution of the proportions of the triad and dyad sequences of units, as well as their microstructure in copolymers. These changes are explained by the formation of macromolecules, both with the participation of free radicals and the stereospecific coordination active centers of polymerization that are formed in the presence of iron complexes.