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Utilization of local-based waste materials can be a challenge due to the resource’s limitations. This study investigated the utilization of rubber tree bark (RTB) as a reductant for mill scale. RTB was blended with coal into five ratios, namely RTB#1–RTB#5. The blends were heated at 1000 °C under argon for 1 h. The char was mixed with scale to produce a carbon-mill scale composite pellet (CCP) with a 1.5 C/O molar ratio. The reduction of CCP was carried out in a tube furnace at 1550 °C for 30 min under argon flowing at 1 L/min. The reduced Fe droplets separate clearly from the residues. The CCP produced from blends RTB#1–RTB#5 shows better reduction with metal of 35.28–39.82 wt.%. The degree of metallization (DOM) ranges between 75.25–84.51%, which is two times higher than that of coal. RTB#3 shows the optimum condition with the highest DOM. CaO in RTB plays a role in forming an ash layer on the metal surface and reacting with Fe2O3 to form a new phase. Utilization of our local-based biomass, such as RTB as a reductant for mill scale, is possible. The consumption of fossil fuel in the process could be decreased by 30%, thus also the production cost.

Abstract A method for the determination of carbaryl in vegetable samples was developed employing peroxidase enzyme extracts from newly excised rubber tree bark strips as a catalyst. The solid phase extraction method QuEChERS was utilized for sample preparation followed by dispersive liquid-liquid microextraction (DLLME) to increase the concentration of the analyte before analysis by UV–Visible spectrophotometry. Parameters influencing this enzymatic development method and efficiency of DLLME were carefully studied. Under selected conditions, absorbance was in proportion to carbaryl concentration in the range of 0.1–3.0 mg L−1 with linear regression (r 2 ) of 0.9999. Limit of detection (LOD) and limit of quantitation (LOQ) were 0.06 mg L−1 and 0.25 mg L−1, respectively. Relative standard deviation (RSD) values for the samples were 2.51–4.06% (n = 7). Good recoveries of carbaryl were obtained in the range of 83–118%. The proposed method proved rapid, reliable and selective for determination of carbaryl in vegetable samples. Graphical abstract Unlabelled Image Highlights • A peroxidase enzymatic reaction was developed for quantification of carbaryl. • The peroxidase enzyme used was extracted from excised rubber tree bark strips. • Crude enzyme extraction was utilized to detect carbaryl without purification steps. • The proposed method was successfully applied to determine carbaryl residues in vegetable samples. • Results obtained from the developed method were not significantly different from results gained by HPLC-UV. [ABSTRACT FROM AUTHOR]

Present study investigates the potential of cassava peel and rubber tree bark for the removal of Cr (VI) from aqueous solution. Removal efficiency of more than 99% was obtained during the kinetic adsorption experiments with dosage of 3.5 g/L for cassava peel and 8 g/L for rubber tree bark. By comparing popular isotherm models and kinetic models for evaluating the kinetics of mass transfer, it was observed that Redlich-Peterson model and Langmuir model fitted well (R2 > 0.99) resulting in maximum adsorption capacity as 79.37 mg/g and 43.86 mg/g for cassava peel and rubber tree bark respectively. Validation of pseudo-second order model and Elovich model indicated the possibility of chemisorption being the rate limiting step. The multi-linearity in the diffusion model was further addressed using multi-sites models (two-site series interface (TSSI) and two-site parallel interface (TSPI) models). Considering the influence of interface properties on the kinetic nature of sorption, TSSI model resulted in low mass transfer rate (5% for cassava peel and 10% for rubber tree bark) compared to TSPI model. The study highlights the employability of two-site sorption model for simultaneous representation of different stages of kinetic sorption for finding the rate-limiting process, compared to the separate equilibrium and kinetic modeling attempts. [ABSTRACT FROM AUTHOR]

Utilization of local-based waste materials can be a challenge due to the resource's limitations. This study investigated the utilization of rubber tree bark (RTB) as a reductant for mill scale. RTB was blended with coal into five ratios, namely RTB#1–RTB#5. The blends were heated at 1000 °C under argon for 1 h. The char was mixed with scale to produce a carbon-mill scale composite pellet (CCP) with a 1.5 C/O molar ratio. The reduction of CCP was carried out in a tube furnace at 1550 °C for 30 min under argon flowing at 1 L/min. The reduced Fe droplets separate clearly from the residues. The CCP produced from blends RTB#1–RTB#5 shows better reduction with metal of 35.28–39.82 wt.%. The degree of metallization (DOM) ranges between 75.25–84.51%, which is two times higher than that of coal. RTB#3 shows the optimum condition with the highest DOM. CaO in RTB plays a role in forming an ash layer on the metal surface and reacting with Fe2O3 to form a new phase. Utilization of our local-based biomass, such as RTB as a reductant for mill scale, is possible. The consumption of fossil fuel in the process could be decreased by 30%, thus also the production cost. [ABSTRACT FROM AUTHOR]