Cu-Al layered double hydroxide (LDH) was intercalated with Keggin ion of polyoxometalate           K4[a-SiW12O40] to form Cu-Al-SiW12O40 LDH. The obtained materials were analyzed by X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) spectroscopy, and Brunaur-Emmett-Teller (BET) surface area analysis. Furthermore, the materials were used as adsorbents of malachite green from aqueous solution. Some variables for adsorption, such as: effect of adsorption times, malachite green concentration, and also adsorption temperature, were explored. The results showed that diffraction at 11.72° on Cu-Al LDH has interlayer distance of 7.56 Å. The intercalation of that LDH with [a-SiW12O40]4− ion resulted increasing interlayer distance to 12.10 Å. The surface area of material was also increased after intercalation from 46.2 m2/g to 89.02 m2/g. The adsorption of malachite green on Cu-Al and          Cu-Al-SiW12O40 LDHs followed pseudo second order kinetic and isotherm Langmuir model with adsorption capacity of Cu-Al and Cu-Al-SiW12O40 LDHs was 55.866 mg/g and 149.253 mg/g, respectively. That adsorption capacity is equal with increasing interlayer space and surface area properties of material after intercalation. Thus, the adsorption of malachite green on Cu-Al and Cu-Al-SiW12O40 LDHs is unique and dominantly occurred on interlayer space of LDH as active site adsorption. Copyright © 2020 BCREC Group. All rights reserved

Reading reviews helps consumers choose the applications, helping companies and developers monitor user satisfaction to improve quality of features and services, read overall and manually could spend the time and laborious, if read at a glance, information not conveyed perfectly. This study analyzes user sentiment Windows Phone Store applications by automatically classifying reviews into positive or negative opinion category. Naïve bayes has good potential because of its simplicity and performance as a model of classifying text on many domains. The model was evaluated using 10 Fold Cross Validation. Measurements were made with the Confusion Matrix and the ROC curve. The accuracy produced in this study is 84.50%, indicating that Naïve Bayes is a good model in classifying text especially in the case of sentiment analysis.

Layered double hydroxide (LDH) Ni/Al-NO3 was synthesized using a coprecipitation method under base condition following with intercalation using Keggin ion [a-SiW12O40]4- to form Ni/Al-[a-SiW12O40] LDH. The LDHs were characterized using XRD, FTIR, BET, and pHpzc analyses. Furthermore, LDHs were applied as adsorbent of iron(II) from aqueous solution. The adsorption process was studied through the effect of adsorption time, the concentration of iron(II), and temperature adsorption. The results show the interlayer distance of LDHs was increased from 7.408 Å to 10.533 Å after intercalation process. The adsorption of iron(II) on LDHs showed that adsorption of iron(II) on both LDHs follows pseudo first-order kinetic model with R2 value is close to one. The adsorption process was spontaneous, with adsorption capacity up to 36.496 mg g-1.

Toko Helai merupakan sebuah toko yang bergerak dalam bidang penjualan fashion hijab, namun demikian dari berbagai jenis pakaian yang dijual tentu tidak semuanya yang laris terjual, ada juga yang kurang laris terjual. Data-data penjualan, pembelian barang maupun pengeluaran tidak terduga pada Toko Helai  ini tidak tersusun dengan baik, sehingga data tersebut hanya berfungsi sebagai arsip bagi toko dan tidak dapat dimanfaatkan untuk pengembangan strategi pemasaran.Oleh karena itu perlu diterapkan data mining menggunakan metode K-Means pada Toko Helai. Metode K-Means dapat diterapkan pada Toko Helai untuk menentukan penjualan baju mana yang sangat laris, laris dan kurang laris. Penerapan metode K-Means pada toko Helai, yaitu dengan cara mengelompokan data stok baju. Kemudian memilih 3 cluster secara acak sebagai centroid awal. Setelah data pada setiap cluster tidak berubah-ubah, maka dapat diketahui hasil akhirnya yaitu yang sangat laris ada 11 artikel, yang laris ada 55 artikel dan 34 artikel untuk yang kurang laris. Kemudian Menerapkan metode K-Means pada Rapidminer dilakukan dengan memasukkan data stok produk yaitu stok awal, stok terjual dan stok akhir yang akan menjadi Database pada Ms.Excel, data tersebut kemudian dikoneksikan ke dalam Tools Rapidminer, dan akan diolah dan dibentuk K-means. Setelah itu, Rapidminer akan menghasilkan produk mana yang sangat laris, laris, dan kurang laris

In this research, NiAl-LDH was synthesized using the coprecipitation method and modified with biochar and graphite to produce NiAl-biochar and NiAl-graphite composite materials. The adsorbent that has been synthesized is used for the application of adsorption of Fe(II) ions in aqueous solution. The resulting material was characterized by XRD (X-ray Diffraction) analysis, spectrophotometer FT-IR, BET analysis for determine the specific surface area and TG-DTA analysis. XRD diffractogram showed that the NiAl-Biochar and NiAl-graphite composite material had the diffraction pattern characteristic of the precursor. LDH that has been modified will have a larger surface area than the precursor. The surface area of NiAl-biochar reaches 438.942 m2/g and the surface area of NiAl-graphitereaches 21.595 m2/g. This composite material supports adsorbents with a large adsorption capacity to adsorb metals. Adsorption of Fe (II) using NiAl-Biochar and NiAl-graphite was stable for five regeneration cycles (<75.30%). The Fe(II) ion adsorption process tends to follow the Langmuir isotherm model which has a maximum capacity value (Qmax) of NiAl-Biochar composite material reaching 20 times with a value of 243.902 mg/g and the NiAl-graphite composite reaching 72.464 mg/g, so that the carbon-based composite material is considered effective. adsorbent to remove Fe(II) ion and can increase the stability of the structure for adsorption regeneration. The results of the analysis of thermodynamic parameters showed that the adsorption process was endothermic, tookplace spontaneously and the solid-liquid phase interface increased according to the increasing degree of disorder.

In this study, NiAl-LDH was modified with hydrochar using the NiAl-Hydrochar composite coprecipitation method. Materials were characterized by XRD and FT-IR analysis. XRD diffractogram and FT-IR spectra show that the NiAl-Hydrochar composite material has the characteristics of the precursors. NiAl-Hydrochar composite materials have a large adsorption capacity to adsorb cationic dyes. The adsorption follows the Langmuir adsorption isotherm model with the maximum capacity (Q max ) of the NiAl-Hydrochar composite material reaching 256.410 mg/g for malachite green and the adsorption process takes place spontaneously and endothermically. The regeneration process of NiAl-Hydrochar composites was more stable and the decrease was not significant (>70%). The selectivity of the dye mixture showed that the adsorbent was more selective for malachite green dye compared to methylene blue and rhodamine-B.

Modification of the layered double hydroxide of CuAl-LDHs by composite with hydrochar (HC) to form CuAl-HC LDH. Material characterization by XRD, FT-IR and SEM analysis was used to prove the success of the modification. The characterization of XRD and FT-IR spectra showed similarities to pure LDH and HC. Selectivity experiments were carried out by mixing malachite green, methylene blue, rhodamine-B, methyl orange, and methyl red to produce the most suitable methyl blue dye for CuAl-LDH, HC and CuAl-HC adsorbents. The effectiveness of CuAl-HC LDH as adsorbent on methylene blue adsorption was tested through several influences such as adsorption isotherm, thermodynamics, and adsorbent regeneration. CuAl-HC LDH adsorption isotherm data shows that the adsorption process tends to follow the Langmuir isotherm model with a maximum adsorption capacity of 175.439 mg/g with a threefold increase compared to pure LDH. The effectiveness of the adsorbent for repeated use reaches five cycles as evidenced by the maximum capacity regeneration data reaching 82.2%, 79.3%, 77.9%, 76.1%, and 75.8%. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Numerous reports have elucidated the use of biochar (BC) to adsorb dyes from wastewater. However, its applicability for adsorbing Procion Red, which causes carcinogenic and mutagenic effects on aquatic life, has not been studied. In this work, biochar produced from rice husk in Sumatera, Indonesia was used as a biosorbent for Procion Red removal from aqueous systems. Rice husk-BC was characterised using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, surface area specific analysis, and scanning electron microscopy (SEM) for mor-phological analysis. The characterisation showed a (002) reflection peak at 2θ = 23° with broad and quite intense diffraction, which indicates reflection of electromagnetic waves by silicates, oxides and carbon present in the rice husk-BC. The surface area and SEM morphologies confirm that after pyrolysis, the surface of the rice husk changed. The FTIR spectra confirm the presence of functional groups such as the carboxylic acids and aromatic compounds. The surface area of rice husk-BC was up to ten times that of its raw material. The results of adsorption studies indicate that adsorption of Procion Red on rice husk-BC follows a pseudo-second-order (PSO) reaction with a rate constant of 0.044 min-1 and Langmuir isotherm models with a coefficient of correlation close to unity. The maximum adsorption capacity increased from 36.900 mg g-1 for the rice husk to 84.034 for the rice husk-BC. Thermodynamic analysis showed positive enthalpy and entropy, indicating that Procion Red adsorption is endothermic; thus, the Gibbs energy values decreased with increase in temperature, indicating that high temperatures are favourable for the adsorption process. Furthermore, the study of adsorption of Procion Red on rice husk-BC and regeneration of the adsorption capacity of rice husk-BC showed the largest drop in the fourth and last cycle.