Synthesis of Poly(hydroxamic acid) Ligand from Polymer Grafted Khaya Cellulose for Transition Metals Extraction

A cellulose-graft-poly(methyl acrylate) was synthesized by free radical initiating process and the ester functional groups were converted into the hydroxamic acid ligand. The intermediate and final products are characterized by FT-IR, FESEM, HR-TEM and XPS technique. The pH of the solution acts as a key factor in achieving optical color signals of metalcomplexation. The reflectance spectra of the[Cu-ligand]n+ complex was found to be a highest absorbance at 99.8 % at pH 6 and it was increased upon increasing of Cu2+ ion concentrations and a broad peak at 700 nm was observed which indicated the charge transfer (π-π transition) metals-Cu complex. The adsorption capacity of copper was found to be superior (336 mg g-1)rather than other transition metals such as Fe3+, Co3+, Cr3+, Ni2+, Mn2+ and Zn2+ were 310, 295, 288, 250, 248 and 225 mg g-1, respectively at pH 6. The experimental data of all metal ions fitted significantly with the pseudo-second-order rate equation. The transition metal ions sorption onto ligand were well fitted with the Langmuir isotherm model (R2>0.99), which suggested that the cellulose-based adsorbent known as poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability of the poly(hydroxamic acid) ligand was checked by the sorption/desorption process up to ten cycles without any significant loss in its original sensing and removal performances

Synthesis of poly(hydroxamic acid) ligand from polymer grafted corn-cob cellulose for transition metals extraction

Poly(hydroxamic acid) ligand was synthesized using ester functionalities of cellulose-graft-poly(methyl acrylate) copolymer, and products are characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy analysis. The poly(hydroxamic acid) ligand was utilized for the sensing and removal of transition metal ions form aqueous solutions. The solution pH is found a key factor for the optical detection of metal ions, and the reflectance spectra of the [Cu-ligand]n+ complex were observed to be the highest absorbance 99.5% at pH?6. With the increase of Cu2+ ion concentration, the reflectance spectra were increased, and a broad peak at 705?nm indicated that the charge transfer (p-p transition) complex was formed. The adsorption capacity with copper was found to be superior, 320?mg?g-1, and adsorption capacities for other transition metal ions were also found to be good such as Fe3+, Mn2+, Co3+, Cr3+, Ni2+, and Zn2+ were 255, 260, 300, 280, 233, and 223?mg?g-1, respectively, at pH?6. The experimental data show that all metal ions fitted well with the pseudo-second-order rate equation. The sorption results of the transition metal ions onto ligand were well fitted with Langmuir isotherm model (R2?>?0.98), which implies the homogenous and monolayer character of poly(hydroxamic acid) ligand surface. Eleven cycles sorption/desorption process were applied to verify the reusability of this adsorbent. The investigation of sorption and extraction efficiency in each cycle indicated that this new type of adsorbent can be recycled in many cycles with no significant loss in its original detection and removal capability

Poly(amidoxime) ligand derived from waste palm fiber for the removal of heavy metals from electroplating wastewater

A waste material known as palm oil empty fruit bunch (EFB) is used as a source of cellulose for the development of polymeric materials for the removal of metal ions from industrial wastewater. A poly(acrylonitrile)-grafted palm cellulose copolymer was synthesized by a conventional free radical initiating process followed by synthesis of a poly(amidoxime) ligand by oximation reaction. The resulting products were characterized by FT-IR, FE-SEM, EDX, TGA, DSC, and XPS. The poly(amidoxime) ligand was used to coordinate with and extract a series of transition metal ions from water samples. The binding capacity (qe) of the ligand with the metal ions such as copper, iron, cobalt, nickel, and lead were 260, 210, 168, 172, and 272 mg g−1 , respectively at pH 6. The adsorption process followed the pseudo-first-order kinetic model (R2 > 0.99) and as well as the Freundlich isotherm model (R2 > 0.99) indicating the occurrence of a multi-layer adsorption process in the amidoxime ligand adsorbent. Results from reusability studies show that the ligand can be recycled for at least 10 cycles without any significant losses to its initial adsorption capacity. The synthesized polymeric ligand was shown to absorb heavy metals from electroplating wastewater with up to 95% efficiency

Canopy precipitation interception in a lowland tropical forest in relation to stand structure

It is generally accepted that vegetation provides important ecosystem services especially in term of rainfall partitioning. This study aims to evaluate the influence of canopy structure namely crown area (CA), diameter at breast height (DBH), tree height (TH) and crown spread (CS) and stand density on the partitioning of rainfall. Twelve throughfall plots of 20 x 20 m with 64 gauges randomly placed within each plot were established. For stemflow measurements, all trees within a 100 m2 plot within the study area were collared. Interception loss was computed as the difference between precipitation and throughfall plus stemflow. Throughfall ranged from 73.47 - 82.32 % of the gross rainfall. Stemflow was found to be roughly around 2.01% of the gross rainfall. Highest interception was 24.52 % attributed to the plot having the highest above ground biomass (AGB) density. The relation between canopy interception and forest structure were analyzed by regression method. Multiple regression analysis on the potential influence of stand structure to the throughfall percentage shows that all the forest structures variables measured in this study are negatively correlated to the amount of throughfall generated. This study suggests that forests with higher value of DBH, CA, CS and TH had higher interception rate

Polymer ligands derived from jute fiber for heavy metal removal from electroplating wastewater

Industrial operations, domestic and agricultural activities worldwide have had major problems with various contaminants caused by environmental pollution. Heavy metal pollution in wastewater also a prominent issue; therefore, a well built and economical treatment technology is demanded for pollution-free wastewater. The present work emphasized pure cellulose extracted from jute fiber and further modification was performed by a free radical grafting reaction, which resulted in poly (methyl acrylate) (PMA)-grafted cellulose and poly(acrylonitrile)-grafted cellulose. Subsequently, poly (hydroxamic acid) and poly(amidoxime) ligands were prepared from the PMA-grafted cellulose and PAN-grafted cellulose, respectively. An adsorption study was performed using the desired ligands with heavy metals such as copper, cobalt, chromium and nickel ions. The binding capacity (qe) with copper ions for poly (hydroxamic acid) is 352 mg g−1 whereas qe for poly(amidoxime) ligand it was exhibited as 310 mg g−1. Other metal ions (chromium, cobalt and nickel) show significance binding properties at pH 6. The Langmuir and Freundlich isotherm study was also performed. The Freundlich isotherm model showed good correlation coefficients for all metal ions, indicating that multiple-layers adsorption was occurred by the polymer ligands. The reusability was evaluated and the adsorbents can be reused for 7 cycles without significant loss of removal performance. Both ligands showed outstanding metals removal capacity from the industrial wastewater as such 98% of copper can be removed from electroplating wastewater and other metals (cobalt, chromium, nickel and lead) can also be removed up to 90%

Toxic Metal Ions Removal from Electroplating Wastewater Using Polymer Chelating

Background: Empty fruit bunch (EFB) is a type of biomass waste product formed during the production process of palm oil. In the present work, EFB was used to prepare a cellulose-graftcopolymer which can be converted into poly(amidoxime)-poly(hydroxamic acid) ligands suitable for the removal of heavy metals from electroplating wastewater. Methods and Results: Poly(amidoxime)-poly(hydroxamic acid) ligands were synthesized from the poly(acrylonitrile-co-methyl acrylate) grafted palm cellulose and were analyzed via FT-IR and FESEM. The binding capacity (qe) with the metals ions such as copper (Cu2+), iron (Fe3+), cobalt (Co2+), nickel (Ni2+) and lead (Pb2+) were 341, 290, 284, 204 and 482 mg g-1, respectively at pH 6. The pseudo-first-order kinetic model is fitted with the results confirming heavy metal adsorption. The isotherm study was conducted using a linear plot of the Langmuir isotherm where results were significantly different from the experimental value (maximum adsorption, qe), indicating that adsorption does not occur on a single layer. However, the coefficient of the correlation values obtained using the Freundlich isotherm model were acceptable (R2>0.99), and it was concluded that adsorption was multilayered with some metal ions. Conclusion: The polymeric ligands synthesized here showed excellent adsorption of heavy metals from electroplating wastewater containing a notable amount of copper and iron metal ions

Synthesis of tapioca cellulose-based poly (hydroxamic acid) ligand for heavy metals removal from water

A graft copolymerization was performed using free radical initiating process to prepare the poly(methyl acrylate) grafted copolymer from the tapioca cellulose. The desired material is poly(hydroxamic acid) ligand, which is synthesized from poly(methyl acrylate) grafted cellulose using hydroximation reaction. The tapioca cellulose, grafted cellulose and poly(hydroxamic acid) ligand were characterized by Infrared Spectroscopy and Field Emission Scanning Electron Microscope. The adsorption capacity with copper was found to be good, 210 mg g¡1 with a faster adsorption rate (t1/2 D 10.5 min). The adsorption capacities for other heavy metal ions were also found to be strong such as Fe3C, Cr3C, Co3C and Ni2C were 191, 182, 202 and 173 mg g¡1, respectively at pH 6. To predict the adsorption behavior, the heavy metal ions sorption onto ligand were well-fitted with the Langmuir isotherm model (R2 > 0.99), which suggest that the cellulose-based adsorbent i.e., poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability was checked by the sorption/desorption process for six cycles and the sorption and extraction efficiency in each cycle was determined. This new adsorbent can be reused in many cycles without any significant loss in its original removal performances

Bornean Pygmy Elephant habitat usage of natural salt licks in Segaliud Lokan Forest Reserve

Bornean pygmy elephant (Elephas maximus borneensis) is crucial in the forests ecosystem as it plays a vital role as a forest engineer. As such, it is crucial to conduct more research to contribute to the conservation of this species. This study examined the pygmy elephant usage of natural salt lick in Segaliud Lokan Forest Reserve (SLFR), also known as FMU19B. Salt lick is vital to maintain wildlife health. This study investigated the elephant's visitation frequency and examined its activity pattern in the natural salt lick area. A camera trap survey was conducted from November 2019 till August 2020. Four natural salt licks (C50SL, C56SL, C59SL and C60SL), and three non-salt licks (C50NSL, C56NSL, and C59&C60NSL) was selected. The data were analysed using descriptive and statistical analysis. The results show a higher visitation frequency at the salt lick area than the non-salt lick area (p<0.01). The salt lick at C59 was the most frequently visited by the elephant. The activity pattern displayed by the Bornean pygmy elephant shows a higher degree of nocturnal activity (73.3%). This information is essential for the timber concession forest managers to design the conservation work for the species in balancing with the timber extraction activity

Synthesis of poly (hydroxamic acid) ligand from polymer grafted khaya cellulose for transition metals extraction

A cellulose-graft-poly(methyl acrylate) was synthesized by free radical initiating process and the ester functional groups were converted into the hydroxamic acid ligand. The intermediate and final products are characterized by FT-IR, FE-SEM, HR-TEM and XPS technique. The pH of the solution acts as a key factor in achieving optical color signals of metal complexation. The reflectance spectra of the [Cu-ligand]n+ complex was found to be a highest absorbance at 99.8 % at pH 6 and it was increased upon increasing of Cu2+ ion concentrations and a broad peak at 700 nm was observed which indicated the charge transfer (π-π transition) metals-Cu complex. The adsorption capacity of copper was found to be superior (336 mg g−1) rather than other transition metals such as Fe3+, Co3+, Cr3+, Ni2+, Mn2+ and Zn2+ were 310, 295, 288, 250, 248 and 225 mg g-1, respectively at pH 6. The experimental data of all metal ions fitted significantly with the pseudo-second-order rate equation. The transition metal ions sorption onto ligand were well fitted with the Langmuir isotherm model (R2>0.99), which suggested that the cellulose-based adsorbent known as poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability of the poly(hydroxamic acid) ligand was checked by the sorption/desorption process up to ten cycles without any significant loss in its original sensing and removal performances