IntroductionThe widespread use of heavy metals and their compounds by modern industries has resulted in the release of large quantities of this element into the environment. These inorganic micropollutants are of great concern because they are non-biodegradable, highly toxic and have a probable carcinogenic effect. If they are directly discharged into sewers, their presence reduces the effectiveness of biological treatment [1, 2, 3]. Among heavy metals, chromium is one of the most important environmental problems. Most chromium is released into aqueous wastes as Cr(VI) and Cr(III). A wide range of technologies are available to remove Cr(IV) and Cr(III) from wastewater. Cr(VI) in liquid waste is more hazardous than Cr(III). Removal of Cr(VI) is more difficult than that of Cr(III). The removal of Cr(VI) from liquid waste has been carried out by various researchers, for example the adsorption process using chemicals as adsorbents. Using chemicals as adsorbents is not environmentally friendly. It is therefore necessary to look for another alternative environmentally friendly adsorbent. The use of a biosorbent to absorb heavy metals such as Cr(VI) is very promising as it is environmentally friendly. A number of researches have used biosorbent for the treatment of Cr(VI)-containing wastewater. Sudiarta [4] uses algae to absorb Cr(III), Aprilia Susanti [5] uses peanut skins as a bio-absorbent to absorb Cibacron Red reactive dyes and Ajeng et al [6] uses chitosan from shells crab to absorb copper ions. Sutrasno et al. [7] conducted research using guava peel to absorb Cr(VI) metal ions. The results obtained showed that the absorption efficiency of Cr (VI) is greater than 90% at pH 2. This research uses ...... middle of paper ...... of Pseudo-Second Order to Cr(VI) Elimination with a biosorbent dose of 1 gram. Based on Figures 3 and 4, it can be concluded that the absorption process of Cr(VI) using guava leaves follows pseudo second order with a k value of 14.5825 g/mg.menit and qe value of 0.1291 mg/g and R2 of 0.9967, so get the equation:(5)ConclusionsFrom the present study, it can be concluded that the contact time is directly proportional to the efficiency and ability of sorption. The results showed that the sorption capacity and efficiency are higher under acidic (pH = 4) and alkaline (pH = 8) conditions. The calculation results show that the sorption kinetics of the reaction followed pseudo second order. The sorption efficiency and capacity using guava leaves reached their optimum level with a contact time of 30 minutes under the current experimental conditions..