Nowadays, industrial activity in the world has grown very fast. In addition to induces positive impacts, the growth of industry also generates a new problem for the environment and so we need to search an effective and efficient handling ways of negative impacts such as waste. One example of pollutions due to industrial wastes is a pollution caused by waste containing in dissolved heavy metals. Waste with a high content of heavy metals could be dangerous pollutants. One of heavy metals that are harmful is chromium. Chromium contained in waste usually has a valence of three (Cr3+) and valence of six (Cr6+). Heavy metals such as chromium waste derived from metal plating industry ...view middle of the document...
The results showed that guava bark had a chromium ion adsorption by more than 90 % at pH = 2. This research uses guava leaves as a bio-sorbent. Leaves are a porous parts of the plant, so it can be used as an adsorbent. Besides guava leaves contain tannins. Tannins can be found in almost all types of green plants both higher plants and lower plants with levels and different qualities. Tannins are polyphenolic compounds that can bind heavy metals and tannin can also absorb pathogenic bacteria so that can cure diarrhea. Beside guava leaves is a porous material, the principle of absorption by tannins underlying the use of guava leaves as a biosorbent in the absorption of heavy metals from wastewater.
Tannin is a natural polyphenolic compound and an important part of plant secondary elements, soluble in water with a molecular weight of 500-3000 g/mol and able to bind alkaloids, gelatin and protein (Wiryawan, 1999). Tannin content in guava leaves as many as 9-12 % (www.litbang.deptan.go.id ).
Considering of Cr (VI) metal ions was produced a lot by industry in Indonesia, then this biomaterials has a potential to be developed as a bio-sorbent by utilizing waste of guava leaves and also very environmental friendly. Adsorption of chromium metal ions of Cr (VI) using these biomaterials have greater power adsorption compared with adsorption methods that have been developed previously (Subiarto, 2000). In addition the use of bio-sorbent can also add value to guava leaves that have not been used optimally.This research aims is to study the metal ion adsorption capacity of Cr (VI) by biomaterial of guava leaves at various of contact temperature.
Materials and Methods
Preparation of necessary materials include materials procurement such as: (1) guava leaves, (2) distilled water, and (3) a solution of K2Cr2O7 as the source of Cr (VI). While the prepared equipment include: (1) erlemenyer, (2) volume pipette, (3) aluminum foil, (4) separating funnel, (5) measuring cup, (6) magnetic stirrer/water batch; (7) Atomic Absorption Spectrophotometer (AAS), (8) electric oven; (9) mixer; (10) balance; (11) filter paper, and (12) flask.
Figure 1 Scheme of Work Research
Initially, raw materials of guava leaves was cleaned from impurities/dirt by clean water. Then guava leaves was dried using oven dryer at temperature of 50°C until a constant weight obtained. Finally, raw material was refined by using mixer with size of more than 25 mesh to increase the surface area of biosorbent. Preparation of Cr (IV) solution with different concentration. K2Cr2O7 was weighed at determined amount and dissolved with distilled water.
Chrome samples was tested at different contact temperature. Sample of Cr (IV) with specified temperature was put in erlenmeyer containing adsorbent. Residence time for adsorption process was varied. The filtrate was filtered by filter paper and ready to be analyzed using atomic absorption spectrophotometer (AAS). Analysis of...