Rice Husk Bio-Chars as Adsorbent for Methylene Blue and Ethinylestradiol from Water

Biobased adsorbents are eco-friendly materials used for water and wastewater treatment and air cleaning.This research work explores the potential use of rice husk chars as a low-cost adsorbent for pollutants from water,such as methylene blue and ethinylestradiol.Rice husk chars are prepared by combustion of rice husks(RH-Char)or pre-treated rice husks(PT-Char).A third char(M-Char)supplied by a local company which uses rice husks as combustion material is also studied.The chars are characterized by field emission scanning electron microscopy(FE-SEM)in conjunction with energy dispersive X-ray spectroscopy(EDX),X-ray powder diffraction(XRD),and zeta-potential measurements.The three bio-chars are tested as adsorbent for the removal of two wastewater contaminants:methylene blue(MB)and ethinylestradiol(EE2).According to the results,RH-Char and PT-Char present zeta-potential values near−52 mV,whereas M-Char shows a zeta-potential value of−32 mV.Both RH-Char and PTChar are rich in amorphous SiO_(2) and M-Char has crystalline SiO_(2)(cristobalite).The bio-chars remove MB and EE2 efficiently showing the following results for the adsorption capacity of MB(inμmol g^(−1)):769.2(RH-Char),41.2(PT-Char),and 31.7(M-Char).The adsorption capacity values for EE2(inμmol g^(−1))are:33.1(RH-Char),19.1(PT-Char),and 16.9(M-Char).The information gathered in the present work evidences the potential of rice husks bio-chars for bio-remediation and may in future contribute to the conversion of a side-stream from the rice industry into value-added materials.

Study on cationic dye adsorption of bio-chars prepared from thermal-alkaline-pretreated sludge

Sludge bio-char(SC)and thermal-alkaline treated sludge bio-char(TSC)were prepared from municipal sewage sludge(RS)and thermal-alkaline treated sludge sediments(STAS)through fast pyrolysis under nitrogen existence condition to remove cationic red X-GRL(A)and cationic yellow X-6G(B)from aqueous solutions.Results of adsorption experiment show that the adsorption capacities of TSC are better than the adsorption capacities of SC.The highest adsorption capacity of 47.65 mg/g for A and 45.41mg/g for B are obtained by TSC in an isotherm experiment at 2.0 g/L dosage and 25°C temperature.TSC adsorption for the two kinds of cationic dyes can be well fitted by pseudo-second-order kinetics model and Langmuir isotherm model.

Effect of reduction roasting by using bio-char derived from empty fruit bunch on the magnetic properties of Malaysian iron ore

Beneficiation of Malaysian iron ore is becoming necessary as iron resources are depleting. However, the upgrading process is challenging because of the weak magnetic properties of Malaysian iron ore. In this study, bio-char derived from oil palm empty fruit bunch （EFB） was utilized as an energy source for reduction roasting. Mixtures of Malaysian iron ore and the bio-char were pressed into briquettes and subjected to reduction roasting processes at 873-1173 K. The extent of reduction was estimated on the basis of mass loss, and the mag-netization of samples was measured using a vibrating sample magnetometer （VSM）. When reduced at 873 K, the original goethite-rich ore was converted into hematite. An increase in temperature to 1073 K caused a significant conversion of hematite into magnetite and enhanced the magnetic susceptibility and saturation magnetization of samples. The magnetic properties diminished at 1173 K as the iron ore was par-tially reduced to wustite. This reduction roasting by using the bio-char can assist in upgrading the iron ore by improving its magnetic proper-ties

Catalytic Pyrolysis of Soybean Oil with CaO/Bio-Char Based Catalyst to Produce High Quality Biofuel

In this paper,CaO/bio-char was synthesized by directly co-pyrolysis of Ca(OH)_(2) and rice straw,and used as catalyst to catalytic pyrolysis of soybean oil to produce high quality biofuel.In this co-pyrolysis process,CaO particles has been successfully embedded on the bio-char surface.During the catalytic pyrolysis process,CaO/biochar showed a good catalytic performance on the deoxygenation of soybean oil.Pyrolysis temperature affected the pyrolysis reactions and pyrolytic products distributions dramatically,higher pyrolysis temperature lead to seriously cracking reactions,lower bio-oil yield and higher gases yield,and lower pyrolysis temperature lead to higher bio-oil yield with higher oxygenated compounds content and lower hydrocarbons contents,the suitable pyrolysis temperature was around 650℃.Under the optimal conditions(650℃ with WHSV at 6.4 h^(−1) and carrier gas flow rate at 100 ml/min),the selectivity(%)of hydrocarbons in the bio-oil was more than 90%.CaO/bio-char catalyst still shows good catalytic deoxygenation activity after 4 cycles.1 g of CaO/bio-char catalyst can catalyze pyrolysis of 32 g of soybean oil to produce high-quality liquid fuel.Bio-char based catalyst has been proved to be a promising catalyst for catalytic conversion of triglyceride-based lipids into high quality liquid biofuel.

Adsorption of Lead (II) and Copper (II) Ions from Mono Synthetic Aqueous Solutions Using Bio-Char from <i>Ficus natalensis</i>Fruits

Many science-based institutions in most developing countries use heavy metal containing salts in practical teaching sessions. The commonly used chemicals are the salts of lead (II) and copper (II) and the wastes generated end up into the environment when untreated. Thus, a study was done to remove lead (II) and copper (II) ions from mono synthetic aqueous solution using bio-char from Ficus natalensis fruits (FNF). This was done at varied pH, contact time, temperature, bio-char dosage level, salinity and metal ion concentration using the batch approach. The residual metal concentrations were determined using the atomic absorption spectrophotometer. The optimum pH for the adsorption of copper (II) and lead (II) ions was found to be 4.0 and 5.0 respectively. The maximum percentage adsorption of copper (II) and lead (II) by the FNF bio-char was established at 60 minutes contact time, 47.5°C and 0.4 g adsorbent dose. Increase in the metal ion concentration and the presence of interfering ions in the aqueous solution lead to decrease in the percentage adsorption. The highest adsorption capacity was found to be 161.29 mg/g and 1250 mg/g for copper (II) and lead (II) ions respectively. The thermodynamic parameters indicated the feasibility of the adsorption of copper (II) and lead (II) on the bio-char of FNF. Thus, bio-char from FNF may be used as an adsorbent in waste management where copper (II) and lead (II) ions are present at a concentration range of between 5 and 100 mg/l.

Effect of Tannin in Green Tea By-Product in Combination with Bio-Char Supplemented into Basal Beef Cattle Diet on Nutrient Digestibility, Methane Production and Animal Performance

The experiment was conducted by using 20 bulls of Lai Sind cattle (a cross breed between Red Sindhi and local Vietnam yellow cattle) from 15 - 16 months of age, weighed approximately 154 - 156 kg, housed individually with provision of adequate feed trough and free access to water to evaluate the effect of tannin sourced from green tea by-product and addition of bio-char on methane production and animal performance. The experimental diets were formulated by replacing elephant grass in basal diet by bio-char and green tea by-product with the replacement of 0.5 - 1 bio-char and 3% - 5% green tea by-products, respectively to make the content of tannin in the diet of 7.3 g and 12.5 g tannin per kg dry matter. Results from this study revealed that bio-char and green tea by-product included into the diet with different levels had significantly affected on the feed intake, as the increasing level of tannin in the diet tended to increase the feed intake. The inclusion of green tea by-product in the diet which resulted in the content of tannin in the diet of 12.5 g/kg DM had significantly reduced methane emission without altering animal performance, thus the inclusion of 0.5% bio-char and 5% of green tea by-product can be applied in order to mitigate methane emission, thus contributed to environment protection.

Pyrolysis of Oil Palm Residues in a Fixed Bed Tubular Reactor

Searching for alternative energy sources continues to grow in recent times due to the fear of energy insecurity in the near future and environmental and sociopolitical issues associated with the use of fossil fuel. Among the renewable energy sources, biomass is the only source that has carbon in its building blocks which can be processed to liquid fuel. In this study, pyrolysis of oil palm residues (trunk, frond and empty fruit bunch) was carried out in a fixed bed tubular reactor under nitrogen atmosphere at 30 mL/min, 30?C/min heating rate and 600?C reaction temperature. Pyrolysis products (bio-oil, bio-char and non-condensable gas) were characterized. Water content, acidity (pH), higher heating value (HHV) and oxygen content of the bio-oil varied between 39.28 - 43 wt%, 2.92 - 3.20, 19.29 - 21.92 MJ/kg and 58.47 - 59.85 wt% respectively. Low pH, highwater and oxygen contents in the oil make it unsuitable for being used as fuel and therefore require upgrading. Scanning electron microscopy and ultimate analysis of the bio-char suggests that it is a porous material and consists mainly carbon between 82.22 - 84.96 wt% and has HHV in the range of 25.98 - 27.65 MJ/kg. This may be used as solid biofuel, adsorbent and source of carbon. High percentage of hydrogen (H2) and carbon monoxide (CO) were observed in the non-condensable gas which may be processed to transportation fuel via Fisher-Tropsch process. Oil palm residues represent good source of renewable energy when all the pyrolysis products are efficiently utilized.

Turning teawaste particles into magnetic bio-sorbents particles for arsenic removal from wastewater:Isotherm and kinetic studies

The primary objective of this research was to assess the potential of magnetic bleached biochar(MBBC)as a cost-effective adsorbent for arsenic removal.To achieve this,locally collected tea wastes underwent meticulous cleaning,bleaching,and modifications via thermal and chemical treatments.Both non-magnetic and magnetic biochar adsorbents were thoroughly characterized using Fourier transform-infrared spectroscopy(FT-IR)and thermo-gravimetric analysis(TGA).Subsequently,the adsorptive performance of MBBC in removing arsenic from wastewater samples was investigated,considering various crucial parameters such as adsorbent-adsorbate contact time,concentration of As,temperature,adsorbent dosage,and the regeneration-ability of the adsorbent.The experimental data for the adsorption process were best represented by the Langmuir isotherm,indicating its suitability for the MBBC adsorbent.Remarkably,the MBBC demonstrated a maximum Langmuir adsorption capacity of approximately 714 mg/g at room temperature,highlighting its efficiency as an arsenic adsorbent.Furthermore,the Lagergren's Pseudo-second order kinetic model proved to be the most suitable for describing the adsorption kinetics,confirming the chemisorption nature of the process.The results also indicated that the adsorption process is endothermic and feasible,suggesting its viability for practical applications.Taking all findings into account,the comprehensive analysis strongly supports the potential use of MBBC as a highly promising and cost-effective adsorbent for efficiently removing arsenic from aqueous samples.This research contributes valuable insights to the field of wastewater treatment and offers a sustainable and environmentally friendly solution for tackling arsenic contamination in water sources.

Effects of reaction temperature,time and particle size on switchgrass microwave pyrolysis and reaction kinetics

This study investigated microwave pyrolysis of switchgrass with particle sizes from 0.5 mm to 4 mm and determined the effects of reaction temperature and time on the yields of bio-oil,syngas,and bio-char.A prediction model was satisfactorily developed to describe the bio-oil conversion yield as a function of reaction temperature and time.Second-order reaction kinetics was also developed to model the switchgrass pyrolysis.Switchgrass with different particle sizes was found to be similarly pyrolyzed by microwave heating.The research results indicated that thermochemical conversion reactions can take place rapidly in large-sized switchgrass by using microwave pyrolysis.GC-MS analysis indicates that the bio-oil contained a series of important and useful chemical compounds:phenols,aliphatic hydrocarbons,aromatic hydrocarbons,and furan derivatives.These chemical compounds evolved were related to the pyrolysis conditions.

Fabrication of Fe/C Composites as Effective Electromagnetic Wave Absorber by Carbonization of Pre-magnetized Natural Wood Fibers

With the increasing usage of varied electronic devices,the induced electromagnetic interference(EMI)irradiation pollution has become a novel environmental pollution besides of water and air pollutions,drawing a great of interests from the scientists to address EMW radiation problem via designing various electromagnetic wave(EMW)absorbers,which is supposed to be with lightweight,thin thickness,wide effective absorbing bandwidth and strong absorbing capacity.One kind of the most attractive absorbers is magnetic carbon composites.Here,we successfully synthesized porous structural C/Fe composites by in-situ carbonization of pre-prepared Fe_(3)O_(4)/wood fibers at 1000℃.The EMW absorption property of C/Fe composites is excellent with a minimum RL value of-32.67 dB at 9.86 GHz,a matching thickness of 2.2 mm and a wide response bandwidth of 14.5 GHz.This excellent absorption performance is proved to be due to the continuous network of Fe_(3)O_(4)/Fe/Fe_(3)C hybrids,permitting optimal impedance matching,the strongest dielectric loss and the optimal magnetic loss.Moreover,the interface polarizations of Fe-Fe_(3)C and Fe_(3)O_(4)-Fe interfaces,are positive to improve the microwave absorption performance.

Value-addition of water hyacinth and para grass through pyrolysis and hydrothermal liquefaction

Hydrothermal liquefaction(HTL)and pyrolysis(Py)of Loktak lake biomass mixture of water hyacinth(WH)and para grass(PG)were carried out at 260-300℃ and 300-500℃ to compare the products yield and chemical characteristics of the products.In case of HTL,the maximum bio-oil yield was obtained 13.34 wt.%at 280℃ while for Py,the maximum bio-oil yield was observed 38.8 wt.%at 350℃.The obtained bio-oils and bio-chars were analyzed using GC-MS,FT-IR,NMR,TGA,TOC,and SEM.GC-MS analysis of the bio-oils were showed that the HTL bio-oil majorly contains of nitrogen containing compounds whereas the Py bio-oil contains majority of phenolic compounds.Other compounds like ketones,alcohols,acids were also observed in bio-oil.Higher intensity broad band at 3300-3500 cm^(−1) was observed in the Py bio-oil compared to HTL bio-oil.TGA and proximate analysis of bio-char revealed the higher devolatilization occured during the HTL compared to Py process.The surface morphology of the HTL bio-char was found to be rough and fragmented as compared to the pyrolysis bio-char,clearly showing the biomass macromolecules breakdown differently in HTL and Py process.