This study reports the development of bio-based adsorbent by utilizing coffee endocarp (CE) waste as a raw material for lead (Pb) removal from liquid wastewater. The effect of NaOH and HCl as activation precursors on the characteristics and performance of the resulting adsorbents was investigated. The prepared adsorbents were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Surface Area Analyzer (SAA). The characterization results confirm the positive role of the activation by either NaOH or HCl in enhancing the surface properties of the resulting adsorbents. The chemical activations removed most of impurities leading to smoother surface, pore size enlargement and enhanced surface area to pore volume ratio, which result in an enhanced adsorption capacity and Pb removal efficiency. The raw adsorbent shows 57.7% of Pb removal efficiency and sorption capacity of 174.4 mg/g. On the other hand, after the chemical treatment using HCl and NaOH, the Pb removal efficiencies increased up to 63.9% and 89.86%, with adsorption capacity of 193 and 271.58 mg/g, respectively. Though both activated sorbents demonstrate better adsorption performance compared to the non-activated CE, overall results reveal that the NaOH-activated sorbent offers better characteristic and performance than the HCl-activated sorbent.

Adsorption been a popular low-cost and environmentally friendly method that can be used to reduce heavy metals in wastewater especially with the use of biomass-sourced sorbents. In this study, the adsorbent was prepared from the coffee shell. The Performance of the prepared adsorbent was studied on the adsorption of Pb(II). The initial concentration of Pb(II) solution used was 300 mg/L and contact time was varied to 0, 30, 60, 90, 120 and 150 minutes. The characteristics of the sorbent were studied in terms of moisture content, ash content, and adsorption of I2. Further characterizations of the coffee shell sorbent were also carried out using Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red Spectrophotometer (FTIR), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Surface Area Analyzer (SAA). The characterization results showed that the prepared sorbent meets the quality requirements according to SNI 06-3730-1995. The results from the adsorption process revealed that the maximum absorption capacity that can be performed by sorbent was 170.26 mg/g at the equilibrium time of 90 minutes. In conclusion, the coffee shell can be a potential biomass material to prepare adsorbent with high removal performance of heavy metal.

In this work, the removal of SO 2 , HC, and CO gases from incineration emission is conducted by means of absorption process using the low-cost sorbent based on Ca(OH) 2 material. The main aim of this research is to enhance the reactivity of Ca(OH) 2 sorbent by using diatomaceous earth (DE) as a source of silica and compost as a bio-sorbent. The calcium sorbent is made from hydrated lime acquired in the local area and modified with DE and compost through a simple mixing technique. Besides the effects of DE and compost addition, other variables such as sorption temperature and height of bed are also studied. The results confirm that combining Ca(OH) 2 sorbent with diatomaceous earth and compost successfully enhanced the removal performance of incineration emission gases. In addition, it is also found that the height of the bed and temperature sorption influence gas absorption efficiency. At bed height of 6 cm and temperature of 150°C, Ca(OH) 2 /DE/compost sorbent showcase the best absorption performance of CO, SO 2 and HC gases with absorption efficiency of CO, SO 2, and HC gas is 48.76%, 57.53%, and 65.38%, respectively. Diatomaceous earth generally contains CaO, SiO 2, and Al 2 O 3 . The reaction between SiO 2 with Ca(OH) 2 to form calcium silicate hydrate which has a porosity and high reactivity. The compost contains bacteria as a bio-sorbent that can convert CO to CO 2 and CH 4 . Both of these minerals are proven to be promising supporting materials in sorbent fabrication.