Facile synthesis of polyethylenimine-modified sugarcane bagasse adsorbent for removal of anionic dye in aqueous solution

Many studies have reported that surface modification of various type of materials by using polyethylenimine (PEI), usually necessitate to be combined with the crosslinkers, namely glutaradehyde, sodium tripolyphosphate, etc. The sugarcane bagasse (SB) is a fibrous agricultural waste derived from sugarcane stalks residue which has rich-cellulose content that makes it amenable to surface functionalization for tailored application. Thus, it is possible for SB material to modify by using solely PEI and eliminate crosslinking step. In this study, SB was used as supporting material for modified PEI to produce polyethylenimine-modified sugarcane bagasse (PmSB) for the adsorption of Reactive Black 5 (RB5) dyes from aqueous solution. The effects of contact time (60 – 300 min), adsorbent dosage (0.05 – 0.15 g); initial dye concentration (0.01 – 0.10 g/L), pH (5 - 9) and temperature (30 – 70 °C) were varied to evaluate the performance of the PSB under different experimental conditions. The kinetics study revealed that the adsorption experimental data fitted the pseudo second order model. The equilibrium adsorption data also fitted the Langmuir model with R2 of 0.99 and maximum monolayer capacity of 25 mg/g. The thermodynamic parameters suggest that the RB5 dye adsorption by PEI modified SB was spontaneous, exothermic and exhibited chemisorption. The adsorbent can be regenerated up to 4 cycles with the percentage dye removal greater than 80%). Therefore, the PmBS adsorbent has proven that the PEI is solely sufficient as modifying agents for SB material, even without an assistance of crosslinker reagents for removal of RB5 dye in aqueous solution

Kinetics, thermodynamics, isotherm and regeneration analysis of chitosan modified pandan adsorbent

There has been increased interest of chitosan as a dye adsorbent. Nonetheless, the chitosan tends to form bonding between their monomer chains that result in a rigid structure which affects its capability for adsorption. This is prime reason many recent studies modified chitosan through various modifications. However, most modifications involve chemical additive agents as well as complex procedures that are conducted under strong condition. Not much research consider low-cost organic materials as modifying agent. The purpose of this work is to investigate the performance of chitosan modified with pandan leaves in the adsorption of reactive black 5 (RB5). Modified chitosan-pandan (MCP) adsorbent was synthesized by simple wet impregnation under mild conditions. The MCP was characterized using Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area analysis. Batch adsorption was conducted to study the effect of retention time (0–60 min), pH (3–11), initial dye concentration (100–1000 mg/L) and temperature (25–80 °C). Kinetics, isotherm, thermodynamics and regeneration evaluation were also performed on the adsorption data. The kinetics data obtained fitted well to the pseudo-second order model, indicating the role of chemisorption with the influence of intraparticle diffusion. For isotherm study, the data is best fitted to the Langmuir model (R2 = 0.91) with maximum adsorption of 169.49 mg/g. Thermodynamics analysis showed that the adsorption is feasible, endothermic and occurred spontaneously. MCP has been regenerated up to 5 times with percentage removal above 50% by washing with distilled water only. In conclusion, natural polyphenols from pandan leaves have been incorporated into chitosan to prepare high-efficiency adsorbent with satisfactory performance in RB5 removal from aqueous media. The MCP is a new promising biodegradable adsorbent for removal of dyes from textile wastewater

Synthesis and application of polyacrylamide grafted magnetic cellulose flocculant for palm oil wastewater treatment

Accumulation of organic load in palm oil mill wastewater has become a major issue of concern. In this study, a new polyacrylamide grafted onto magnetic cellulose (PAM-g-MagCell) was successfully produced by microwave assisted synthesis and used as flocculant for the removal of total suspended solid (TSS), turbidity, chemical oxygen demand (COD) and colour. The physical and chemical properties of the PAM-g-MagCell were characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometer, zeta potential and elemental analysis. A jar test method was employed to perform flocculation, which was evaluated on anaerobically treated palm oil mill effluent suspension. The flocculants dosage, initial pH and settling time were varied to study the effects of these variables on contaminant removal from wastewater. The best conditions for the removal of TSS, turbidity, COD, and colour were achieved at flocculants dosage of 1.5 »g/L, pH of 8.0 and settling time of 30 »min. Under these conditions, the removal of TSS, turbidity, COD, and colour were 82.97 %, 88.62 %, 53.23 % and 91.76 %, respectively. The PAM-g-MagCell also showed better performance when compared with cellulose, magnetic cellulose (MagCell), polyacrylamide, and alum. In conclusion, all the results show that the PAM-g-MagCell as alternative flocculant has great application prospects in the removal of organic matters from palm oil mill wastewater