Utilization of galactomannan from spent coffee grounds as coagulant aid to treat synthetic Congo red wastewater

Over the last few years, there is a significant growth in research exploring natural based coagulant due to its various benefits to decrease or even substitute the usage of inorganic chemical coagulants. Polysaccharide based coagulant and coagulant aid is a promising source for this purpose, due to its abundance. In this study, we reported utilization of galactomannan extracted from spent coffee grounds as natural coagulant aid in coagulation of Congo red synthetic wastewater. The coagulation was done at fixed dosage of FeCl3 (160 mg/L) and pH of 6. The effect of galactomannan as coagulant aid was observed by varying galactomannan dosage (0-140 mg/L) and Congo red concentration (20–70 mg/L). It was found that galactomannan as coagulant aid could increase the removal of Congo red, around 30–90% removal, depends on Congo red concentration, compared FeCl3 only (0–65%). The coagulation adsorption study was also investigated using Langmuir, Freundlich, and Brunauer – Emmet – Teller (BET) isotherm models. It was found that Congo red coagulation using FeCl3 only was following Langmuir isotherm, indicating monolayer – homogenous formation during the coagulation. On the other hand, with the presence of galactomannan the coagulation was best described by BET isotherm, indicating multilayer – heterogeneous adsorption, possibly due to interparticle bridging of galactomannan during colloid aggregation. The findings in this study suggest synergistic effect of galactomannan and FeCl3 in the coagulation process and proved potential of galactomannan from spent coffee grounds as natural coagulant aid.

A prudent approach for the removal of copper (II) and cadmium (II) ions from aqueous solutions using indigenous Mactra aequisulcata shells

In this study, the raw seashells of Mactra aequisulcata, of class Bivalvia and phylum Mollusca were employed as an adsorbent to remove copper (II) and cadmium (II) metal ions from aqueous solution. The characterization of shells was performed using FTIR, EDX and SEM, BET isotherm and point of zero charge (pHpzc). Batch experiments were performed to assess various factors on the biosorption efficiency. Maximum adsorption of both metals ions conveniently found at 0.4 g L-1 adsorbent dose, pH 5 and at 303 K. Maximum biosorption capacities for Cu2+ and Cd2+ were 59.57 and 38.12 mg g-1, respectively. The Langmuir isotherm model was found to be the best fit for the acquired equilibrium data. Thermodynamic and kinetic parameters presented that the process was feasible, exothermic and followed pseudo-first order.

Sorption Isotherms and Thermodynamics of Direct Dye onto the Nano Poly(amidoamine) Dendrimer Treated Jute Yarn

Background: In this study, the poly(amidoamine) (PAMAM) G-2 dendrimer was applied to the jute yarn. Methods: Untreated and dendrimer treated jute yarns were then dyed with Direct Yellow 24. Thermodynamic parameters of dyed samples, free energy (ΔG°), the enthalpy (ΔH°), and the entropy (ΔS°) were also evaluated. Results: Dendrimer treated jute yarn showed higher dye sorption compare to untreated jute yarn. The values of ΔH° and ΔG° indicated that the sorption process was exothermic and spontaneous at low temperature. Conclusion: Freundlich isotherm was found to be the optimum isotherm for untreated and BET isotherm defined for dendrimer treated jute yarn.

Removal of Manganese from Aqueous Solution Using Indonesian Peat

Peat can be used as a natural adsorbent due to its humic acid content having various active functional groups such as carboxylates and hydroxyl groups. Peat soil samples obtained from Pelalawan district, Riau province of Indonesia were selected and their adsorption capacities were investigated using Mn(II) solution as a model solution. The raw peat samples were first prepared by drying at 110°C for 12 h. The adsorption experiment was conducted in batch test using Mn(II) solutions for 360 mins at pH of 5.2 as optimum conditions. The peat samples were analyzed using the Fourier Transform Infrared Spectroscopy, Surface Area Analysis and Scanning Electron Microscopy- Energy Dispersive Spectroscopy. The obtained adsorption data were fitted using Langmuir, Freundlich and BET isotherm models. It was found that the adsorption data followed the Langmuir isotherm model with correlation coefficients (R2) ranging between 0.9866-0.9997 and the adsorption capacities were between 11.99-22.94 mg/g.

Perbandingan efektivitas dekolorisasi fotokatalitik metilen biru dan metil jingga menggunakan semikonduktor ZnO pada variasi pH

The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Semiconductor under UV-LED radiation has been studied at varied pH. ZnO have been synthesized using co-precipitation method. The Scanning Electron Microscopy (SEM) result showed that the synthesized ZnO has a hexagonal structure with the particle size range 0.125 to 0.5 µm. The BET isotherm characterization showed the synthesized ZnO has a specific surface area (SBET), mesoporous volume and micropore volume of 60.20 m2/g, 0.541 cm3/g and 0.02 cm3/g, respectively. The observation of the effect of pH to the photocatalytic activity showed that the highest removal percentage occurred at pH 9 with the value of 95.64% for methylene blue and occurred at pH 3 with the value of 6.236% for methyl orange.

Perbandingan Efektivitas Dekolorisasi Fotokatalitik Metilen Biru dan Metil Jingga Menggunakan Semikonduktor ZnO pada Variasi pH

The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Semiconductor under UV-LED radiation has been studied at varied pH. ZnO have been synthesized using co-precipitation method. The Scanning Electron Microscopy (SEM) result showed that the synthesized ZnO has a hexagonal structure with the particle size range 0.125 to 0.5 µm. The BET isotherm characterization showed the synthesized ZnO has a specific surface area (SBET), mesoporous volume and micropore volume of 60.20 m2/g, 0.541 cm3/g and 0.02 cm3/g, respectively. The observation of the effect of pH to the photocatalytic activity showed that the highest removal percentage occurred at pH 9 with the value of 95.64% for methylene blue and occurred at pH 3 with the value of 6.236% for methyl orange.

Isolation of Silica-Lignin Composites from Rice Husk and Their Adsorption to Cr(VI)

<p>Rice husk is the most abundant agricultural waste in Indonesia. It can be used as a precursor for multifunctional materials such as silica-lignin composite for adsorbents. Silica-lignin can reduce heavy metal content in an industrial waste, such as the content of Cr(VI). This study aims to isolate and characterize silica-lignin composite, and determines the isotherm type of silica-lignin for hexavalent chromium adsorption. The isolation from rice husk used an alkali extraction method. Confirmation of typical functional groups in the silica-lignin composite was characterized by FTIR, while the morphology was characterized by SEM, respectively. The results reveal that the silica-lignin isolation was successfully performed. FTIR spectra indicate a typical wavenumber of the silica-lignin. The SEM image of the composite showed homogeneous morphology. The silica-lignin adsorption process on hexavalent chromium followed a Brunauer–Emmett–Teller (BET) isotherm type indicated by multilayer adsorption with a surface area of 948.8421 mg. g^-1<em>.</em></p>

Activity Reduction of 232Th and 40K from Simulated Underground Water Using a Clay-Based Membrane

In this research, the activities of 232Th and 40K in simulated underground water were reduced using inexpensive clay-based membrane. Starch (10 and 15 wt%) was added to the clay, compacted and fired up to 1300°C to produce the porous membranes. The characterization of the raw clay and the produced membranes was conducted using XRF, XRD, TGA/DTA, BET and FESEM. The activities of 232Th and 40K in the waste and permeated water were counted using gamma spectroscopy. The produced membranes were having pore sizes in the range 39.68-46.10nm; from the BET isotherm, it shows the membranes produced are mesoporous. Also, the steady flux of the filtered water was found to be in the range 3.83×10-7-1.77×s10-6 m3m-2s-1. Activities of thorium and potassium in the permeated water were found to be 4.57-5.61 Bq/l and 15.49-25.19 Bq/l respectively. This shows that inexpensive clay can be used to reduce the activities of thorium and potassium in underground water from mining, fracking and produced water from oil and gas.

Modeling Gas Adsorption in Marcellus Shale With Langmuir and BET Isotherms

Summary Production from shale-gas reservoirs plays an important role in natural-gas supply in the United States. Horizontal drilling and multistage hydraulic fracturing are the two key enabling technologies for the economic development of these shale-gas reservoirs. It is believed that gas in shale reservoirs is mainly composed of free gas within fractures and pores and adsorbed gas in organic matter (kerogen). It is generally assumed in the literature that the monolayer Langmuir isotherm describes gas-adsorption behavior in shale-gas reservoirs. However, in this work, we analyzed four experimental measurements of methane adsorption from the Marcellus Shale core samples that deviate from the Langmuir isotherm, but obey the Brunauer-Emmett-Teller (BET) isotherm. To the best of our knowledge, it is the first time to find that methane adsorption in a shale-gas reservoir behaves similar to multilayer adsorption. Consequently, investigation of this specific gas-desorption effect is important for accurate evaluation of well performance and completion effectiveness in shale-gas reservoirs on the basis of the BET isotherm. The difference in calculating original gas in place (OGIP) on the basis of both isotherms is discussed. We also performed history matching with one production well from the Marcellus Shale and evaluated the contribution of gas desorption to the well's performance. History matching shows that gas adsorption obeying the BET isotherm contributes more to overall gas recovery than gas adsorption obeying the Langmuir isotherm, especially at early time in production. This work provides better understanding of gas desorption in shale-gas reservoirs and updates our current analytical and numerical models for simulation of shale-gas production.